Image processing apparatus and method

ABSTRACT

An object of the present invention is to separate in real time a captured image into a foreground component image and a background component image. An image captured by an image-capturing unit  74  is separated into a foreground component image and a background component image, which are stored in an image storage unit  72 . A billing processor  75  performs billing processing to charge fees for separating the image. A separating portion  91  performs motion-blur processing of the separated foreground component image and outputs the processed foreground component image and the background component image to a synthesizer  92 . The synthesizer  92  combines the input motion-blur-processed foreground component image and the separated background component image to synthesize an image and displays the synthesized image on a display unit  73 . The present invention is applicable to a camera terminal device.

TECHNICAL FIELD

The present invention relates to image processing apparatuses andmethods, and more particularly, to an image processing apparatus andmethod for separating in real time a captured image into a foregroundcomponent image and a background component image and for performingreal-time motion-blur processing of the foreground component image.

BACKGROUND ART

Technology for processing captured images has gradually become popularand widely used.

Hitherto, motion blur that arises when two different images are combinedor when an image of a moving subject is captured is eliminated byseparately combining the images after the images have been captured orby eliminating the motion blur.

In the latter case, that is, when the image of the moving subject iscaptured, there is a method for eliminating in real time motion blurthat arises due to the motion. Specifically, for example, as shown inFIG. 1A, when an image of a subject swinging a golf club is captured, adisplayed image includes a blurred golf club due to the motion of thegolf club. The effect that arises when such a blurred image is displayedis the so-called motion blur.

In order to eliminate the motion blur in real time, as shown in FIG. 1B,one possible method uses a high-speed camera to capture an image. Whenan image is captured by the high-speed camera, the amount of luminanceat the time the image is captured is insufficient (since one shutterperiod is short, the amount of light obtained is small, and hence, theluminance is insufficient). The subject needs to be irradiated withspecial intense light, or, as shown in FIG. 2, irradiated with a flashof intense light at the same time as the shutter is pressed, and animage of the subject needs to be captured by the high-speed camera.

In the foregoing method, the image synthesis processing cannot beperformed in real time. In the synthesis processing, if there is noimage needed for synthesis, an image must again be captured at the sameplace. There is a method for performing the motion-blur eliminationprocessing in real time. For example, capturing an image of a wildanimal at night for the purpose of ecological observation using theforegoing method may frighten the wild animal, which is the subject,since the foregoing method involves using intense lighting. As a result,the natural ecology may not be observed.

DISCLOSURE OF INVENTION

The present invention has been made in view of the above-describedbackground. Accordingly, it is an object of the present invention toachieve in real time synthesis processing and motion-blur adjustmentprocessing in processing an image.

An image processing apparatus of the present invention includes inputmeans for inputting image data which is formed of a predetermined numberof pixel data obtained by a predetermined number of image-capturingdevices including pixels, the image-capturing devices each having a timeintegrating function; mixture-ratio estimating means for estimating amixture ratio for a mixed area in the image data input from the inputmeans, the mixed area including a mixture of foreground objectcomponents forming a foreground object of the image data and backgroundobject components forming a background object of the image data;separation means for separating in real time, on the basis of themixture ratio estimated by the mixture-ratio estimating means, the imagedata input from the input means into a foreground component image formedof the foreground object components forming the foreground object of theimage data and a background component image formed of the backgroundobject components forming the background object of the image data; andstorage means for storing in real time the foreground component imageand the background component image, which are separated by theseparation means.

The image processing apparatus may further include image-capturing meansfor capturing an image which is formed of the image data formed of pixelvalues determined in accordance with the intensity of light forming theimage which is integrated with respect to time in each pixel by thepredetermined number of image-capturing devices for converting the lightforming the image into electrical charge and integrating with respect totime the electrical charge generated by the photoelectric conversion.

The image processing apparatus may further include image-capturingcommand means for giving a command to the image-capturing means tocapture the image; and image-capturing billing means for executingbilling processing in response to the command from the image-capturingcommand means.

The image processing apparatus may further include image display meansfor displaying the foreground component image and the backgroundcomponent image which are separated in real time by the separation meansand the foreground component image and the background component imagewhich are already stored in the storage means; image specifying meansfor specifying a desired foreground component image and backgroundcomponent image from among the foreground component image and thebackground component image which are separated in real time by theseparation means and which are displayed by the image display means andthe foreground component image and the background component image whichare already stored in the storage means and which are displayed by theimage display means; and combining means for combining the desiredforeground component image and background component image which arespecified by the specifying means.

The image processing apparatus may further include combining commandmeans for giving a command to the combining means to combine images; andcombining billing means for executing billing processing in response tothe command from the combining command means.

The image processing apparatus may further include storage command meansfor giving a command to the storage means, the command instructingwhether or not to store in real time the foreground component image andthe background component image which are separated by the separationmeans; and storage billing means for executing billing processing inresponse to the command from the storage command means.

The image processing apparatus may further include motion-blur adjustingmeans for adjusting motion blur of the foreground component image whichis separated in real time by the separation means or the foregroundcomponent image which is already stored in the storage means.

The image processing apparatus may further includemotion-blur-adjusted-image display means for displaying themotion-blur-adjusted foreground component image generated by themotion-blur adjusting means.

The image processing apparatus may further include combining means forcombining the motion-blur-adjusted foreground component image generatedby the motion-blur adjusting means and the background component image.The motion-blur-adjusted-image display means may display an imagegenerated by combining, by the combining means, the motion-blur-adjustedforeground component image generated by the motion-blur adjusting meansand the background component image.

The image processing apparatus may further include processing-timemeasuring means for measuring time required by the motion-blur adjustingmeans to adjust the motion blur of the foreground component image; andmotion-blur-adjustment billing means for executing billing processing inaccordance with the time measured by the processing-time measuringmeans.

The image processing apparatus may further include operation-timemeasuring means for measuring operation time thereof; and operationbilling means for executing billing processing in accordance with thetime measured by the operation-time measuring means.

An image processing method of the present invention includes an inputstep of inputting image data which is formed of a predetermined numberof pixel data obtained by a predetermined number of image-capturingdevices including pixels, the image-capturing devices each having a timeintegrating function; a mixture-ratio estimating step of estimating amixture ratio for a mixed area in the image data input in the inputstep, the mixed area including a mixture of foreground object componentsforming a foreground object of the image data and background objectcomponents forming a background object of the image data; a separationstep of separating in real time, on the basis of the mixture ratioestimated in the mixture-ratio estimating step, the image data input inthe input step into a foreground component image formed of theforeground object components forming the foreground object of the imagedata and a background component image formed of the background objectcomponents forming the background object of the image data; and astorage step of storing in real time the foreground component image andthe background component image, which are separated in the separationstep.

The image processing method may further include an image-capturing stepof capturing an image which is formed of the image data formed of pixelvalues determined in accordance with the intensity of light forming theimage which is integrated with respect to time in each pixel by thepredetermined number of image-capturing devices for converting the lightforming the image into electrical charge and integrating with respect totime the electrical charge generated by the photoelectric conversion.

The image processing method may further include an image-capturingcommand step of giving a command to the image-capturing step to capturethe image; and an image-capturing billing step of executing billingprocessing in response to the command in the image-capturing commandstep.

The image processing method may further include an image display step ofdisplaying the foreground component image and the background componentimage which are separated in real time in the separation step and theforeground component image and the background component image which arealready stored in the storage step; an image specifying step ofspecifying a desired foreground component image and background componentimage from among the foreground component image and the backgroundcomponent image which are separated in real time in the separation stepand which are displayed in the image display step and the foregroundcomponent image and the background component image which are alreadystored in the storage step and which are displayed in the image displaystep; and a combining step of combining the desired foreground componentimage and background component image which are specified in thespecifying step.

The image processing method may further include a combining command stepof giving a command to the combining step to combine images; and acombining billing step of executing billing processing in response tothe command in the combining command step.

The image processing method may further include a storage command stepof giving a command to the storage step, the command instructing whetheror not to store in real time the foreground component image and thebackground component image which are separated in the separation step;and a storage billing step of executing billing processing in responseto the command in the storage command step.

The image processing method may further include a motion-blur adjustingstep of adjusting motion blur of the foreground component image which isseparated in real time in the separation step or the foregroundcomponent image which is already stored in the storage step.

The image processing method may further include amotion-blur-adjusted-image display step of displaying themotion-blur-adjusted foreground component image generated in themotion-blur adjusting step.

The image processing method may further include a combining step ofcombining the motion-blur-adjusted foreground component image generatedin the motion-blur adjusting step and the background component image.The motion-blur-adjusted-image display step may display an imagegenerated by combining, in the combining step, the motion-blur-adjustedforeground component image generated in the motion-blur adjusting stepand the background component image.

The image processing method may further include a processing-timemeasuring step of measuring time required in the motion-blur adjustingstep to adjust the motion blur of the foreground component image; and amotion-blur-adjustment billing step of executing billing processing inaccordance with the time measured in the processing-time measuring step.

The image processing method may further include an operation-timemeasuring step of measuring operation time thereof; and an operationbilling step of executing billing processing in accordance with the timemeasured in the operation-time measuring step.

A program in a recording medium of the present invention includes aninput control step of controlling the inputting of image data which isformed of a predetermined number of pixel data obtained by apredetermined number of image-capturing devices including pixels, theimage-capturing devices each having a time integrating function; amixture-ratio estimating control step of controlling the estimation of amixture ratio for a mixed area in the image data input in the inputcontrol step, the mixed area including a mixture of foreground objectcomponents forming a foreground object of the image data and backgroundobject components forming a background object of the image data; aseparation control step of controlling the separation in real time, onthe basis of the mixture ratio estimated in the mixture-ratio estimatingcontrol step, of the image data input in the input control step into aforeground component image formed of the foreground object componentsforming the foreground object of the image data and a backgroundcomponent image formed of the background object components forming thebackground object of the image data; and a storage control step ofcontrolling the storing, in real time, of the foreground component imageand the background component image, which are separated in theseparation control step.

The program may further include an image-capturing control step ofcontrolling the capturing of an image which is formed of the image dataformed of pixel values determined in accordance with the intensity oflight forming the image which is integrated with respect to time in eachpixel by the predetermined number of image-capturing devices forconverting the light forming the image into electrical charge andintegrating with respect to time the electrical charge generated by thephotoelectric conversion.

The program may further include an image-capturing command control stepof controlling the giving of a command to the image-capturing controlstep to capture the image; and an image-capturing billing control stepof controlling the execution of billing processing in response to thecommand in the image-capturing command control step.

The program may further include an image display control step ofcontrolling the displaying of the foreground component image and thebackground component image which are separated in real time in theseparation control step and the foreground component image and thebackground component image which are already stored in the storagecontrol step; an image specifying control step of controlling thespecifying of a desired foreground component image and backgroundcomponent image from among the foreground component image and thebackground component image which are separated in real time in theseparation control step and which are displayed in the image displaycontrol step and the foreground component image and the backgroundcomponent image which are already stored in the storage control step andwhich are displayed in the image display control step; and a combiningcontrol step of controlling the combining of the desired foregroundcomponent image and background component image which are specified inthe specifying control step.

The program may further include a combining command control step ofcontrolling the giving of a command to the combining control step tocombine images; and a combining billing control step of controlling theexecution of billing processing in response to the command in thecombining command control step.

The program may further include a storage command control step ofcontrolling the giving of a command to the storage control step, thecommand instructing whether or not to store in real time the foregroundcomponent image and the background component image which are separatedin the separation control step; and a storage billing control step ofcontrolling the execution of billing processing in response to thecommand in the storage command control step.

The program may further include a motion-blur adjusting control step ofcontrolling the adjustment of motion blur of the foreground componentimage which is separated in real time in the separation control step orthe foreground component image which is already stored in the storagecontrol step.

The program may further include a motion-blur-adjusted-image displaycontrol step of controlling the displaying of the motion-blur-adjustedforeground component image generated in the motion-blur adjustingcontrol step.

The program may further include a combining control step of controllingthe combining of the motion-blur-adjusted foreground component imagegenerated in the motion-blur adjusting control step and the backgroundcomponent image. The motion-blur-adjusted-image display control step maydisplay an image generated by combining, in the combining control step,the motion-blur-adjusted foreground component image generated in themotion-blur adjusting control step and the background component image.

The program may further include a processing-time measuring control stepof controlling the measurement of time required in the motion-bluradjusting step to adjust the motion blur of the foreground componentimage; and a motion-blur-adjustment billing control step of controllingthe execution of billing processing in accordance with the time measuredin the processing-time measuring control step.

The program may further include an operation-time measuring control stepof controlling the measurement of operation time thereof; and anoperation billing control step of controlling the execution of billingprocessing in accordance with the time measured in the operation-timemeasuring control step.

A program of the present invention causes a computer to perform aprocess including an input control step of controlling the inputting ofimage data which is formed of a predetermined number of pixel dataobtained by a predetermined number of image-capturing devices includingpixels, the image-capturing devices each having a time integratingfunction; a mixture-ratio estimating control step of controlling theestimation of a mixture ratio for a mixed area in the image data inputin the input control step, the mixed area including a mixture offoreground object components forming a foreground object of the imagedata and background object components forming a background object of theimage data; a separation control step of controlling the separation inreal time, on the basis of the mixture ratio estimated in themixture-ratio estimating control step, of the image data input in theinput control step into a foreground component image formed of theforeground object components forming the foreground object of the imagedata and a background component image formed of the background objectcomponents forming the background object of the image data; and astorage control step of controlling the storing, in real time, of theforeground component image and the background component image, which areseparated in the separation control step.

The process may further include an image-capturing control step ofcontrolling the capturing of an image which is formed of the image dataformed of pixel values determined in accordance with the intensity oflight forming the image which is integrated with respect to time in eachpixel by the predetermined number of image-capturing devices forconverting the light forming the image into electrical charge andintegrating with respect to time the electrical charge generated by thephotoelectric conversion.

The process may further include an image-capturing command control stepof controlling the giving of a command to the image-capturing controlstep to capture the image; and an image-capturing billing control stepof controlling the execution of billing processing in response to thecommand in the image-capturing command control step.

The process may further include an image display control step ofcontrolling the displaying of the foreground component image and thebackground component image which are separated in real time in theseparation control step and the foreground component image and thebackground component image which are already stored in the storagecontrol step; an image specifying control step of controlling thespecifying of a desired foreground component image and backgroundcomponent image from among the foreground component image and thebackground component image which are separated in real time in theseparation control step and which are displayed in the image displaycontrol step and the foreground component image and the backgroundcomponent image which are already stored in the storage control step andwhich are displayed in the image display control step; and a combiningcontrol step of controlling the combining of the desired foregroundcomponent image and background component image which are specified inthe specifying control step.

The process may further include a combining command control step ofcontrolling the giving of a command to the combining control step tocombine images; and a combining billing control step of controlling theexecution of billing processing in response to the command in thecombining command control step.

The process may further include a storage command control step ofcontrolling the giving of a command to the storage control step, thecommand instructing whether or not to store in real time the foregroundcomponent image and the background component image which are separatedin the separation control step; and a storage billing control step ofcontrolling the execution of billing processing in response to thecommand in the storage command control step.

The process may further include a motion-blur adjusting control step ofcontrolling the adjustment of motion blur of the foreground componentimage which is separated in real time in the separation control step orthe foreground component image which is already stored in the storagecontrol step.

The process may further include a motion-blur-adjusted-image displaycontrol step of controlling the displaying of the motion-blur-adjustedforeground component image generated in the motion-blur adjustingcontrol step.

The process may further include a combining control step of controllingthe combining of the motion-blur-adjusted foreground component imagegenerated in the motion-blur adjusting control step and the backgroundcomponent image. The motion-blur-adjusted-image display control step maydisplay an image generated by combining, in the combining control step,the motion-blur-adjusted foreground component image generated in themotion-blur adjusting control step and the background component image.

The process may further include a processing-time measuring control stepof controlling the measurement of time required in the motion-bluradjusting control step to adjust the motion blur of the foregroundcomponent image; and a motion-blur-adjustment billing control step ofcontrolling the execution of billing processing in accordance with thetime measured in the processing-time measuring control step.

The process may further include an operation-time measuring control stepof controlling the measurement of operation time thereof; and anoperation billing control step of controlling the execution of billingprocessing in accordance with the time measured in the operation-timemeasuring control step.

According to an information processing apparatus and method and aprogram of the present invention, image data which is formed of apredetermined number of pixel data obtained by a predetermined number ofimage-capturing devices including pixels is input, the image-capturingdevices each having a time integrating function. A mixture ratio for amixed area in the input image data is estimated, the mixed areaincluding a mixture of foreground object components forming a foregroundobject of the image data and background object components forming abackground object of the image data. On the basis of the estimatedmixture ratio, the input image data is separated in real time into aforeground component image formed of the foreground object componentsforming the foreground object of the image data and a backgroundcomponent image formed of the background object components forming thebackground object of the image data. The separated foreground componentimage and background component image are stored in real time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a known image processing method.

FIG. 1B illustrates a known image processing method.

FIG. 2 illustrates a known image processing method.

FIG. 3 illustrates the configuration of an embodiment of an imageprocessing system to which the present invention is applied.

FIG. 4 illustrates the configuration of a camera terminal device shownin FIG. 3.

FIG. 5 illustrates the configuration of a television set terminal deviceshown in FIG. 3.

FIG. 6 is a block diagram showing the configuration of the cameraterminal device shown in FIG. 4.

FIG. 7 is a block diagram showing the configuration of the televisionset terminal device shown in FIG. 5.

FIG. 8 is a block diagram illustrating the configuration of a signalprocessor shown in FIG. 6.

FIG. 9 is a block diagram illustrating an image processing apparatus.

FIG. 10 illustrates the image-capturing performed by a sensor.

FIG. 11 illustrates the arrangement of pixels.

FIG. 12 illustrates the operation of a detection device.

FIG. 13A illustrates an image obtained by image-capturing an objectcorresponding to a moving foreground and an object corresponding to astationary background.

FIG. 13B illustrates an image obtained by image-capturing an objectcorresponding to a moving foreground and an object corresponding to astationary background.

FIG. 14 illustrates a background area, a foreground area, a mixed area,a covered background area, and an uncovered background area.

FIG. 15 illustrates a model obtained by expanding in the time directionthe pixel values of pixels aligned side-by-side in an image obtained byimage-capturing an object corresponding to a stationary foreground andan the object corresponding to a stationary background.

FIG. 16 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 17 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 18 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 19 illustrates an example in which pixels in a foreground area, abackground area, and a mixed area are extracted.

FIG. 20 illustrates the relationships between pixels and a modelobtained by expanding the pixel values in the time direction.

FIG. 21 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 22 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 23 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 24 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 25 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 26 is a flowchart illustrating the processing for adjusting theamount of motion blur.

FIG. 27 is a block diagram illustrating an example of the configurationof an area specifying unit 103.

FIG. 28 illustrates an image when an object corresponding to aforeground is moving.

FIG. 29 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 30 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 31 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 32 illustrates the conditions for determining the area.

FIG. 33A illustrates an example of the result obtained by specifying thearea by the area specifying unit 103.

FIG. 33B illustrates an example of the result obtained by specifying thearea by the area specifying unit 103.

FIG. 33C illustrates an example of the result obtained by specifying thearea by the area specifying unit 103.

FIG. 33D illustrates an example of the result obtained by specifying thearea by the area specifying unit 103.

FIG. 34 illustrates an example of the result obtained by specifying thearea by the area specifying unit 103.

FIG. 35 is a flowchart illustrating the area specifying processing.

FIG. 36 is a block diagram illustrating another example of theconfiguration of the area specifying unit 103.

FIG. 37 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 38 illustrates an example of a background image.

FIG. 39 is a block diagram illustrating the configuration of abinary-object-image extracting portion 302.

FIG. 40A illustrates the calculation of a correlation value.

FIG. 40B illustrates the calculation of a correlation value.

FIG. 41A illustrates the calculation of a correlation value.

FIG. 41B illustrates the calculation of a correlation value.

FIG. 42 illustrates an example of a binary object image.

FIG. 43 is a block diagram illustrating the configuration of a timechange detector 303.

FIG. 44 illustrates determinations made by an area determining portion342.

FIG. 45 illustrates an example of determinations made by the time changedetector 303.

FIG. 46 is a flowchart illustrating the area specifying processingperformed by the area specifying unit 103.

FIG. 47 is a flowchart illustrating details of the area specifyingprocessing.

FIG. 48 is a block diagram illustrating still another configuration ofthe area specifying unit 103.

FIG. 49 is a block diagram illustrating the configuration of arobust-processing portion 361.

FIG. 50 illustrates motion compensation performed by a motioncompensator 381.

FIG. 51 illustrates motion compensation performed by the motioncompensator 381.

FIG. 52 is a flowchart illustrating the area specifying processing.

FIG. 53 is a flowchart illustrating details of the robust processing.

FIG. 54 is a block diagram illustrating the configuration of amixture-ratio calculator 104.

FIG. 55 illustrates an example of the ideal mixture ratio α.

FIG. 56 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 57 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 58 illustrates approximation using the correlation of foregroundcomponents.

FIG. 59 illustrates the relationship among C, N and P.

FIG. 60 is a block diagram illustrating the configuration of amixture-ratio estimation processor 401.

FIG. 61 illustrates an example of an estimated mixture ratio.

FIG. 62 is a block diagram illustrating another configuration of themixture-ratio calculator 104.

FIG. 63 is a flowchart illustrating the mixture-ratio calculationprocessing.

FIG. 64 is a flowchart illustrating the processing for calculating theestimated mixture ratio.

FIG. 65 illustrates a straight line for approximating the mixture ratioα.

FIG. 66 illustrates a plane for approximating the mixture ratio α.

FIG. 67 illustrates the relationships of the pixels in a plurality offrames when the mixture ratio α is calculated.

FIG. 68 is a block diagram illustrating another configuration of themixture-ratio estimation processor 401.

FIG. 69 illustrates an example of an estimated mixture ratio.

FIG. 70 is a flowchart illustrating the mixture-ratio estimatingprocessing by using a model corresponding to a covered background area.

FIG. 71 is a block diagram illustrating an example of the configurationof a foreground/background separator 105.

FIG. 72A illustrates an input image, a foreground component image, and abackground component image.

FIG. 72B illustrates an input image, a foreground component image, and abackground component image.

FIG. 73 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 74 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 75 illustrates a model in which pixel values are expanded in thetime direction and the period corresponding to the shutter time isdivided.

FIG. 76 is a block diagram illustrating an example of the configurationof a separating portion 601.

FIG. 77A illustrates examples of a separated foreground component imageand a separated background component image.

FIG. 77B illustrates examples of a separated background component imageand a separated background component image.

FIG. 78 is a flowchart illustrating the processing for separating aforeground and a background.

FIG. 79 is a block diagram illustrating an example of the configurationof a motion-blur adjusting unit 106.

FIG. 80 illustrates the unit of processing.

FIG. 81 illustrates a model in which the pixel values of a foregroundcomponent image are expanded in the time direction and the periodcorresponding to the shutter time is divided.

FIG. 82 illustrates a model in which the pixel values of a foregroundcomponent image are expanded in the time direction and the periodcorresponding to the shutter time is divided.

FIG. 83 illustrates a model in which the pixel values of a foregroundcomponent image are expanded in the time direction and the periodcorresponding to the shutter time is divided.

FIG. 84 illustrates a model in which the pixel values of a foregroundcomponent image are expanded in the time direction and the periodcorresponding to the shutter time is divided.

FIG. 85 illustrates an example of another configuration of themotion-blur adjusting unit 106.

FIG. 86 is a flowchart illustrating the processing for adjusting theamount of motion blur contained in a foreground component imageperformed by the motion-blur adjusting unit 106.

FIG. 87 is a block diagram illustrating an example of anotherconfiguration of the motion-blur adjusting unit 106.

FIG. 88 illustrates an example of a model in which the relationshipsbetween pixel values and foreground components are indicated.

FIG. 89 illustrates the calculation of foreground components.

FIG. 90 illustrates the calculation of foreground components.

FIG. 91 is a flowchart illustrating the processing for eliminatingmotion blur contained in a foreground.

FIG. 92 is a block diagram illustrating another configuration of thefunction of the image processing apparatus.

FIG. 93 illustrates the configuration of a synthesizer 1001.

FIG. 94 is a block diagram illustrating still another configuration ofthe function of the image processing apparatus.

FIG. 95 is a block diagram illustrating the configuration of amixture-ratio calculator 1101.

FIG. 96 is a block diagram illustrating the configuration of aforeground/background separator 1102.

FIG. 97 is a block diagram illustrating still another configuration ofthe function of the image processing apparatus.

FIG. 98 illustrates the configuration of a synthesizer 1201.

FIG. 99 is a flowchart illustrating the synthesis service processingperformed by the camera terminal device.

FIG. 100 is a flowchart illustrating the synthesis service billingprocessing.

FIG. 101 illustrates the synthesis service billing processing.

FIG. 102A illustrates the synthesis service billing processing.

FIG. 102B illustrates the synthesis service billing processing.

FIG. 102C illustrates the synthesis service billing processing.

FIG. 103 illustrates a real-time synthesis service offered by the cameraterminal device.

FIG. 104 illustrates another embodiment of a camera terminal device.

FIG. 105 is a flowchart illustrating the real-time synthesis serviceprocessing performed by the camera terminal device.

FIG. 106 illustrates the real-time synthesis service offered by thecamera terminal device.

FIG. 107 illustrates the real-time synthesis service offered by thecamera terminal device.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 3 illustrates an embodiment of an image processing system accordingto the present invention.

The image processing system of the present invention includes, forexample, a camera terminal device 2, a television terminal device 3, abilling server 5, a financial server (for customer) 6, and a financialserver (for provider) 7, which are connected with one another over anetwork 1, such as the Internet, and which can exchange data with oneanother. The camera terminal device 2 captures images,separates/combines the captured images in real time, and displays theimages. Fees are charged for separating and combining the images. Forexample, provided that the camera terminal device 2 is to be rented out,fees for separating and combining images may be charged by the billingserver 5 via the network 1 so as to transfer the fees from the user'sfinancial server 6 to the provider's (for example, a service providerrenting the camera terminal device 2) financial server 7. The televisionset terminal device 3 separates an image captured by a camera device 4in real time, combines the image portions, and displays the image. Feesfor separating and combining the images are similarly charged as in thecamera terminal device 2.

FIG. 4 illustrates the configuration of the camera terminal device 2according to the present invention. A CPU (Central Processing Unit) 21executes various types of processing according to programs stored in aROM (Read Only Memory) 22 or in a storage unit 28. Programs executed bythe CPU 21 and data are stored in a RAM (Random Access Memory) 23 asrequired. The CPU 21, the ROM 22, and the RAM 23 are connected to eachother by a bus 24.

An input/output interface 25 is also connected to the CPU 21 via a bus44. An input unit 26, which is formed of a keyboard, a mouse, amicrophone, and so on, and an output unit 27, which is formed of adisplay, a speaker, and so on, are connected to the input/outputinterface 25. The CPU 21 executes various types of processing inresponse to a command input from the input unit 26 including a shutterbutton and various input keys. Also, a sensor 26 a serving as animage-capturing device is connected to the input unit 26, and capturedimages are input thereto. The CPU 21 outputs images and audio obtainedas a result of processing to the output unit 27, and the images aredisplayed on an LCD (Liquid Crystal Display) 27 a.

The storage unit 28 connected to the input/output interface 25 is formedof, for example, a hard disk, and stores programs executed by the CPU 21and various types of data. A communication unit 29 communicates with anexternal device via the Internet or another network.

Also, a program may be obtained via the communication unit 29 and storedin the storage unit 28.

A drive 30 connected to the input/output interface 25 drives a magneticdisk 41, an optical disc 42, a magneto-optical disk 43, a semiconductormemory 44, or the like, when such a recording medium is attached to thedrive 30, and obtains a program or data stored in the correspondingmedium. The obtained program or data is transferred to the storage unit28 and stored therein if necessary.

FIG. 5 shows the configuration of the television set 3 according to thepresent invention. The configuration of the television set 3 isbasically the same as that of the camera terminal device 2.Specifically, a CPU 51, a ROM 52, a RAM 53, a bus 54, an input/outputinterface 55, an input unit 56, an output unit 57, a storage unit 58, acommunication unit 59, a drive 60, a magnetic disk 61, an optical disk62, a magneto-optical disk 63, and a semiconductor memory 64 of thetelevision set terminal device 3 correspond to the CPU 21, the ROM 22,the RAM 23, the bus 24, the input/output interface 25, the input unit26, the output unit 27, the storage unit 28, the communication unit 29,the drive 30, the magnetic disk 41, the optical disk 52, themagneto-optical disk 53, and the semiconductor memory 54, respectively,of the camera terminal device 2. In this example, as shown in FIGS. 1Aand 1B, the camera device 4 is connected to the communication unit 59 ofthe television set terminal device 3, and captured images are inputthereto.

Since the basic configurations of the billing server 5, the financialserver (for customer) 6, and the financial server (for provider) 7 aresimilar to that of the television set terminal device 3, descriptionsthereof are omitted.

Referring to FIG. 6, the camera terminal device 2 will now be described.

A signal processor 71 of the camera terminal device 2 displays, on thebasis of an image input from an image-capturing unit 74 (correspondingto a sensor 76 a shown in FIG. 4) or an image input from a unit otherthan the image-capturing unit 74, the input image on a display unit 73without changing the input image. Also, the signal processor 71generates any one of the foreground of the input image, the backgroundof the input image, a synthesized image generated by combining theforeground of the input image and a background prestored in an imagestorage unit 72, a synthesized image generated by combining thebackground of the input image and a foreground prestored in the imagestorage unit 72, a synthesized image generated by combining a foregroundand a background prestored in the image storage unit 72, a foregroundprestored in the image storage unit 72, and a background prestored inthe image storage unit 72 and displays the generated image on thedisplay unit 73.

An image input to the signal controller 71 needs not to be an image.Specifically, when displaying the above-described various output imageson the display unit 73, the signal controller 71 stores the images inthe image storage unit 72 while assigning the ID to each image (the IDis assigned to each of a foreground component image, a backgroundcomponent image, and a synthesized image). By inputting the image IDspecifying the stored image, the signal controller 71 uses, as an inputimage, an image corresponding to the image ID among the images stored inthe image storage unit 72.

A billing processor 75 cooperates with the billing server 5 via thenetwork 1 in performing the billing processing for charging fees for theimage separation processing or image synthesis processing performed bythe signal processor 71. The billing processor 75 stores the ID thereofand, when performing the billing processing, transmits the ID along withthe user ID, authentication information, and the fees to the billingserver 5.

Details of the signal processor 71 will be described later withreference to FIG. 8.

Referring to FIG. 7, the configuration of the television set terminaldevice 3 will now be described. The configuration of the television setterminal device 3 is the same as that of the camera terminal device 2except for the fact that the television set terminal device 3 does notinclude the image-capturing unit 74, which is included in the cameraterminal device 2, and instead includes a tuner 84 for outputting animage captured by the external camera device 4 or an image in the formof an NTSC (National Television Standards Committee) signal generatedfrom electromagnetic waves received by an antenna (not shown) to asignal processor 81. That is, the signal processor 81, an image storageunit 82, a display unit 83, and a billing processor 85 of the televisionset terminal device 3 correspond to the signal processor 71, the imagestorage unit 72, the display unit 73, and the billing processor 75,respectively, of the camera terminal device 2, and descriptions thereofare thus omitted.

With reference to FIG. 8, a description of the configuration of thesignal processor 71 will be given as follows.

A separating portion 91 of the signal processor 71 separates an inputimage input from the image-capturing unit 74, another input image, or animage specified by the image ID and stored in the image storage unit 72into a foreground component image and a background component image andoutputs a desired image to a synthesizer 92. In other words, when theimage to be output, that is, the desired image, is the foregroundcomponent image, only the foreground component image of the separatedimage portions is output to the synthesizer 92. In contrast, when animage required by the image to be output is the background componentimage, only the background component image of the separated imageportions is output to the synthesizer 92. The ID is assigned to eachimage output to the synthesizer 92, and each image is thus stored in theimage storage unit 72. Needless to say, the separating portion 91 canoutput the input image to the synthesizer 92 without separating theinput image. In this case, the separating portion 91 assignees the ID tothe output image and stores the output image in the image storage unit72.

If necessary, the synthesizer. 92 combines the image input from theseparating portion 91 with an image stored in the image storage unit 72to synthesize an image and outputs the synthesized image. Specifically,when outputting the foreground or the background of the input image, thesynthesizer 92 outputs the foreground component image or the backgroundcomponent image input from the separating portion 91 without changingthe foreground component image or the background component image. Whenoutputting a synthesized image generated by combining the foreground ofthe input image and a background prestored in the image storage unit 72or when outputting a synthesized image generated by combining thebackground of the input image and a foreground prestored in the imagestorage unit 72, the synthesizer 92 combines the foreground componentimage or the background component image input from the separatingportion 91 with a background component image or a foreground componentimage prestored in the image storage unit 72 to synthesize an image andoutputs the synthesized image. When outputting a synthesized imagegenerated by combining a foreground and a background prestored in theimage storage unit 72, a foreground prestored in the image storage unit72, or a background prestored in the image storage unit 72, thesynthesizer 92 combines a foreground component image and a backgroundcomponent image prestored in the image storage unit 72 to synthesize animage and outputs the synthesized image or outputs a foregroundcomponent image or a background component image prestored in the imagestorage unit 72 without changing the foreground component image or thebackground component image.

The billing processor 75 performs the billing processing when theseparating portion 91 performs the separation processing or when thesynthesizer 92 performs the combining processing. When the separatingportion 91 does not perform the separation processing and outputs theimage without changing it to the synthesizer 92, or when the synthesizer92 does not perform the combining processing and outputs the imagewithout changing it, fees may not be charged.

FIG. 9 is a block diagram illustrating the separating portion 91.

It does not matter whether the individual functions of the separatingportion 91 are implemented by hardware or software. That is, the blockdiagrams of this specification may be hardware block diagrams orsoftware functional block diagrams.

An input image supplied to the separating portion 91 is supplied to anobject extracting unit 101, an area specifying unit 103, a mixture-ratiocalculator 104, and a foreground/background separator 105.

The object extracting unit 101 extracts a rough image objectcorresponding to a foreground object contained in the input image, andsupplies the extracted image object to a motion detector 102. The objectextracting unit 101 detects, for example, an outline of the foregroundimage object contained in the input image so as to extract a rough imageobject corresponding to the foreground object.

The object extracting unit 101 extracts a rough image objectcorresponding to a background object contained in the input image, andsupplies the extracted image object to the motion detector 102. Theobject extracting unit 101 extracts a rough image object correspondingto the background object from, for example, the difference between theinput image and the extracted image object corresponding to theforeground object.

Alternatively, for example, the object extracting unit 101 may extractthe rough image object corresponding to the foreground object and therough image object corresponding to the background object from thedifference between the background image stored in a built-in backgroundmemory and the input image.

The motion detector 102 calculates a motion vector of the roughlyextracted image object corresponding to the foreground object accordingto a technique, such as block matching, gradient, phase correlation, orpel-recursive technique, and supplies the calculated motion vector andthe motion-vector positional information (which is information forspecifying the positions of the pixels corresponding to the motionvector) to the area specifying unit 103 and a motion-blur adjusting unit106.

The motion vector output from the motion detector 102 containsinformation corresponding to the amount of movement v.

The motion detector 102 may output the motion vector of each imageobject, together with the pixel positional information for specifyingthe pixels of the image object, to the motion-blur adjusting unit 106.

The amount of movement v is a value indicating a positional change in animage corresponding to a moving object in units of the pixel pitch. Forexample, if an object image corresponding to a foreground is moving suchthat it is displayed at a position four pixels away from a referenceframe when it is positioned in the subsequent frame, the amount ofmovement v of the object image corresponding to the foreground is 4.

The object extracting unit 101 and the motion detector 102 are neededwhen adjusting the amount of motion blur corresponding to a movingobject.

The area specifying unit 103 determines to which of a foreground area, abackground area, or a mixed area each pixel of the input image belongs,and supplies information indicating to which area each pixel belongs(hereinafter referred to as “area information”) to the mixture-ratiocalculator 104, the foreground/background separator 105, and themotion-blur adjusting unit 106.

The mixture-ratio calculator 104 calculates the mixture ratiocorresponding to the pixels contained in a mixed area (hereinafterreferred to as the “mixture ratio α”) based on the input image and thearea information supplied from the area specifying unit 103, andsupplies the calculated mixture ratio to the foreground/backgroundseparator 105.

The mixture ratio α is a value indicating the ratio of the imagecomponents corresponding to the background object (hereinafter also bereferred to as “background components”) to the pixel value as expressedby equation (3), which is shown below.

The foreground/background separator 105 separates the input image into aforeground component image formed of only the image componentscorresponding to the foreground object (hereinafter also be referred toas “foreground components”) and a background component image formed ofonly the background components based on the area information suppliedfrom the area specifying unit 103 and the mixture ratio α supplied fromthe mixture-ratio calculator 104, and supplies the foreground componentimage to the motion-blur adjusting unit 106 and a selector 107. Theseparated foreground component image may be set as the final output. Amore precise foreground and background can be obtained compared to aknown method in which only a foreground and a background are specifiedwithout considering the mixed area.

The motion-blur adjusting unit 106 determines the unit of processingindicating at least one pixel contained in the foreground componentimage based on the amount of movement v obtained from the motion vectorand based on the area information. The unit of processing is data thatspecifies a group of pixels to be subjected to the motion-bluradjustments.

Based on the amount by which the motion blur is to be adjusted, which isinput to the separating portion 91, the foreground component imagesupplied from the foreground/background separator 105, the motion vectorand the positional information thereof supplied from the motion detector102, and the unit of processing, the motion-blur adjusting unit 106adjusts the amount of motion blur contained in the foreground componentimage by removing, decreasing, or increasing the motion blur containedin the foreground component image. The motion-blur adjusting unit 106then outputs the foreground component image in which amount of motionblur is adjusted to the selector 107. It is not essential that themotion vector and the positional information thereof be used.

Motion blur is a distortion contained in an image corresponding to amoving object caused by the movement of an object to be captured in thereal world and the image-capturing characteristics of a sensor.

The selector 107 selects one of the foreground component image suppliedfrom the foreground/background separator 105 and the foregroundcomponent image in which the amount of motion blur is adjusted suppliedfrom the motion-blur adjusting unit 106 based on, for example, aselection signal reflecting a user's selection, and outputs the selectedforeground component image.

An input image supplied to the separating portion 91 is discussed belowwith reference to FIGS. 10 through 25.

FIG. 10 illustrates image-capturing performed by a sensor. The sensor isformed of, for example, a CCD (Charge-Coupled Device) video cameraprovided with a CCD area sensor, which is a solid-state image-capturingdevice. An object 112 corresponding to a foreground in the real worldmoves, for example, horizontally from the left to the right, between anobject 111 corresponding to a background and the sensor.

The sensor captures the image of the object 112 corresponding to theforeground together with the image of the object 111 corresponding tothe background. The sensor outputs the captured image in units offrames. For example, the sensor outputs an image having 30 frames persecond. The exposure time of the sensor can be 1/30 second. The exposuretime is a period from when the sensor starts converting input light intoelectrical charge until when the conversion from the input light to theelectrical charge is finished. The exposure time is also referred to asa “shutter time”.

FIG. 11 illustrates the arrangement of pixels. In FIG. 11, A through Iindicate the individual pixels. The pixels are disposed on a plane of acorresponding image. One detection device corresponding to each pixel isdisposed on the sensor. When the sensor performs image-capturing, eachdetection device outputs a pixel value of the corresponding pixelforming the image. For example, the position of the detection device inthe X direction corresponds to the horizontal direction on the image,while the position of the detection device in the Y directioncorresponds to the vertical direction on the image.

As shown in FIG. 12, the detection device, which is, for example, a CCD,converts input light into electrical charge during a periodcorresponding to a shutter time, and stores the converted electricalcharge. The amount of charge is almost proportional to the intensity ofthe input light and the period for which the light is input. Thedetection device sequentially adds the electrical charge converted fromthe input light to the stored electrical charge during the periodcorresponding to the shutter time. That is, the detection deviceintegrates the input light during the period corresponding to theshutter time and stores the electrical charge corresponding to theamount of integrated light. It can be considered that the detectiondevice has an integrating function with respect to time.

The electrical charge stored in the detection device is converted into avoltage value by a circuit (not shown), and the voltage value is furtherconverted into a pixel value, such as digital data, and is output.Accordingly, each pixel value output from the sensor is a valueprojected on a linear space, which is a result of integrating a certainthree-dimensional portion of the object corresponding to the foregroundor the background with respect to the shutter time.

The separating portion 91 extracts significant information embedded inthe output signal, for example, the mixture ratio α, by the storageoperation of the sensor. The separating portion 91 adjusts the amount ofdistortion, for example, the amount of motion blur, caused by themixture of the foreground image object itself. The separating portion 91also adjusts the amount of distortion caused by the mixture of theforeground image object and the background image object.

FIGS. 13A and 13B illustrate an image obtained by image-capturing anobject corresponding to a moving foreground and an object correspondingto a stationary background. FIG. 13A illustrates an image obtained bycapturing a moving object corresponding to a foreground and a stationaryobject corresponding to a background. In the example shown in FIG. 13A,the object corresponding to the foreground is moving horizontally fromthe left to the right with respect to the screen.

FIG. 13B illustrates a model obtained by expanding pixel valuescorresponding to one line of the image shown in FIG. 13A in the timedirection. The horizontal direction shown in FIG. 13B corresponds to thespatial direction X in FIG. 13A.

The values of the pixels in the background area are formed only from thebackground components, that is, the image components corresponding tothe background object. The values of the pixels in the foreground areaare formed only from the foreground components, that is, the imagecomponents corresponding to the foreground object.

The values of the pixels of the mixed area are formed from thebackground components and the foreground components. Since the values ofthe pixels in the mixed area are formed from the background componentsand the foreground components, it may be referred to as a “distortionarea”. The mixed area is further classified into a covered backgroundarea and an uncovered background area.

The covered background area is a mixed area at a position correspondingto the leading end in the direction in which the foreground object ismoving, where the background components are gradually covered with theforeground over time.

In contrast, the uncovered background area is a mixed area correspondingto the trailing end in the direction in which the foreground object ismoving, where the background components gradually appear over time.

As discussed above, the image containing the foreground area, thebackground area, or the covered background area or the uncoveredbackground area is input into the area specifying unit 103, themixture-ratio calculator 104, and the foreground/background separator105 as the input image.

FIG. 14 illustrates the background area, the foreground area, the mixedarea, the covered background area, and the uncovered background areadiscussed above. In the areas corresponding to the image shown in FIGS.13A and 13B, the background area is a stationary portion, the foregroundarea is a moving portion, the covered background area of the mixed areais a portion that changes from the background to the foreground, and theuncovered background area of the mixed area is a portion that changesfrom the foreground to the background.

FIG. 15 illustrates a model obtained by expanding in the time directionthe pixel values of the pixels aligned side-by-side in the imageobtained by capturing the image of the object corresponding to thestationary foreground and the image of the object corresponding to thestationary background. For example, as the pixels aligned side-by-side,pixels arranged in one line on the screen can be selected.

The pixel values indicated by F01 through F04 shown in FIG. 15 arevalues of the pixels corresponding to the object of the stationaryforeground. The pixel values indicated by B01 through B04 shown in FIG.15 are values of the pixels corresponding to the object of thestationary background.

The vertical direction in FIG. 15 corresponds to time, and time elapsesfrom the top to the bottom in FIG. 15. The position at the top side ofthe rectangle in FIG. 15 corresponds to the time at which the sensorstarts converting input light into electrical charge, and the positionat the bottom side of the rectangle in FIG. 15 corresponds to the timeat which the conversion from the input light into the electrical chargeis finished. That is, the distance from the top side to the bottom sideof the rectangle in FIG. 15 corresponds to the shutter time.

The pixels shown in FIG. 15 are described below assuming that, forexample, the shutter time is equal to the frame size.

The horizontal direction in FIG. 15 corresponds to the spatial directionX in FIG. 13A. More specifically, in the example shown in FIG. 15, thedistance from the left side of the rectangle indicated by “F01” in FIG.15 to the right side of the rectangle indicated by “B04” is eight timesthe pixel pitch, i.e., eight consecutive pixels.

When the foreground object and the background object are stationary, thelight input into the sensor does not change during the periodcorresponding to the shutter time.

The period corresponding to the shutter time is divided into two or moreportions of equal periods. For example, if the number of virtual dividedportions is 4, the model shown in FIG. 15 can be represented by themodel shown in FIG. 9. The number of virtual divided portions can be setaccording to the amount of movement v of the object corresponding to theforeground within the shutter time. For example, the number of virtualdivided portions is set to 4 when the amount of movement v is 4, and theperiod corresponding to the shutter time is divided into four portions.

The uppermost line in the diagram corresponds to the first dividedperiod from when the shutter has opened. The second line in the diagramcorresponds to the second divided period from when the shutter hasopened. The third line in the diagram corresponds to the third dividedperiod from when the shutter has opened. The fourth line in the diagramcorresponds to the fourth divided period from when the shutter hasopened.

The shutter time divided in accordance with the amount of movement v isalso hereinafter referred to as the “shutter time/v”.

When the object corresponding to the foreground is stationary, the lightinput into the sensor does not change, and thus, the foregroundcomponent F01/v is equal to the value obtained by dividing the pixelvalue F01 by the number of virtual divided portions. Similarly, when theobject corresponding to the foreground is stationary, the foregroundcomponent F02/v is equal to the value obtained by dividing the pixelvalue F02 by the number of virtual divided portions, the foregroundcomponent F03/v is equal to the value obtained by dividing the pixelvalue F03 by the number of virtual divided portions, and the foregroundcomponent F04/v is equal to the value obtained by dividing the pixelvalue F04 by the number of virtual divided portions.

When the object corresponding to the background is stationary, the lightinput into the sensor does not change, and thus, the backgroundcomponent B01/v is equal to the value obtained by dividing the pixelvalue B01 by the number of virtual divided portions. Similarly, when theobject corresponding to the background is stationary, the backgroundcomponent B02/v is equal to the value obtained by dividing the pixelvalue B02 by the number of virtual divided portions, the backgroundcomponent B03/v is equal to the value obtained by dividing the pixelvalue B03 by the number of virtual divided portions, and the backgroundcomponent B04/v is equal to the value obtained by dividing the pixelvalue B04 by the number of virtual divided portions.

More specifically, when the object corresponding to the foreground isstationary, the light corresponding to the foreground object input intothe sensor does not change during the period corresponding to theshutter time. Accordingly, the foreground component F01/v correspondingto the first portion of the shutter time/v from when the shutter hasopened, the foreground component F01/v corresponding to the secondportion of the shutter time/v from when the shutter has opened, theforeground component F01/v corresponding to the third portion of theshutter time/v from when the shutter has opened, and the foregroundcomponent F01/v corresponding to the fourth portion of the shuttertime/v from when the shutter has opened become the same value. The sameapplies to F02/v through F04/v, as in the case of F01/v.

When the object corresponding to the background is stationary, the lightcorresponding to the background object input into the sensor does notchange during the period corresponding to the shutter time. Accordingly,the background component B01/v corresponding to the first portion of theshutter time/v from when the shutter has opened, the backgroundcomponent B01/v corresponding to the second portion of the shuttertime/v from when the shutter has opened, the background component B01/vcorresponding to the third portion of the shutter time/v from when theshutter has opened, and the background component B01/v corresponding tothe fourth portion of the shutter time/v from when the shutter hasopened become the same value. The same applies to B02/v through B04/v.

A description is given of the case in which the object corresponding tothe foreground is moving and the object corresponding to the backgroundis stationary.

FIG. 17 illustrates a model obtained by expanding in the time directionthe pixel values of the pixels in one line, including a coveredbackground area, when the object corresponding to the foreground ismoving to the right in FIG. 17. In FIG. 17, the amount of movement v is4. Since one frame is a short period, it can be assumed that the objectcorresponding to the foreground is a rigid body moving with constantvelocity. In FIG. 17, the object image corresponding to the foregroundis moving such that it is positioned four pixels to the right withrespect to a reference frame when it is displayed in the subsequentframe.

In FIG. 17, the pixels from the leftmost pixel to the fourth pixelbelong to the foreground area. In FIG. 17, the pixels from the fifthpixel to the seventh pixel from the left belong to the mixed area, whichis the covered background area. In FIG. 17, the rightmost pixel belongsto the background area.

The object corresponding to the foreground is moving such that itgradually covers the object corresponding to the background over time.Accordingly, the components contained in the pixel values of the pixelsbelonging to the covered background area change from the backgroundcomponents to the foreground components at a certain time during theperiod corresponding to the shutter time.

For example, the pixel value M surrounded by the thick frame in FIG. 17is expressed by equation (1) below.M=B02/v+B02/v+F07/v+F06/v  (1)

For example, the fifth pixel from the left contains a backgroundcomponent corresponding to one portion of the shutter time/v andforeground components corresponding to three portions of the shuttertime/v, and thus, the mixture ratio α of the fifth pixel from the leftis ¼. The sixth pixel from the left contains background componentscorresponding to two portions of the shutter time/v and foregroundcomponents corresponding to two portions of the shutter time/v, andthus, the mixture ratio α of the sixth pixel from the left is ½. Theseventh pixel from the left contains background components correspondingto three portions of the shutter time/v and a foreground componentcorresponding to one portion of the shutter time/v, and thus, themixture ratio α of the fifth pixel from the left is ¾.

It can be assumed that the object corresponding to the foreground is arigid body, and the foreground object is moving with constant velocitysuch that it is displayed four pixels to the right in the subsequentframe. Accordingly, for example, the foreground component F07/v of thefourth pixel from the left in FIG. 17 corresponding to the first portionof the shutter time/v from when the shutter has opened is equal to theforeground component of the fifth pixel from the left in FIG. 17corresponding to the second portion of the shutter time/v from when theshutter has opened. Similarly, the foreground component F07/v is equalto the foreground component of the sixth pixel from the left in FIG. 17corresponding to the third portion of the shutter time/v from when theshutter has opened, and the foreground component of the seventh pixelfrom the left in FIG. 17 corresponding to the fourth portion of theshutter time/v from when the shutter has opened.

It can be assumed that the object corresponding to the foreground is arigid body, and the foreground object is moving with constant velocitysuch that it is displayed four pixels to the right in the subsequentframe. Accordingly, for example, the foreground component F06/v of thethird pixel from the left in FIG. 17 corresponding to the first portionof the shutter time/v from when the shutter has opened is equal to theforeground component of the fourth pixel from the left in FIG. 17corresponding to the second portion of the shutter time/v from when theshutter has opened. Similarly, the foreground component F06/v is equalto the foreground component of the fifth pixel from the left in FIG. 17corresponding to the third portion of the shutter time/v from when theshutter has opened, and the foreground component of the sixth pixel fromthe left in FIG. 17 corresponding to the fourth portion of the shuttertime/v from when the shutter has opened.

It can be assumed that the object corresponding to the foreground is arigid body, and the foreground object is moving with constant velocitysuch that it is displayed four pixels to the right in the subsequentframe. Accordingly, for example, the foreground component F05/v of thesecond pixel from the left in FIG. 17 corresponding to the first portionof the shutter time/v from when the shutter has opened is equal to theforeground component of the third pixel from the left in FIG. 17corresponding to the second portion of the shutter time/v from when theshutter has opened. Similarly, the foreground component F05/v is equalto the foreground component of the fourth pixel from the left in FIG. 17corresponding to the third portion of the shutter time/v from when theshutter has opened, and the foreground component of the fifth pixel fromthe left in FIG. 17 corresponding to the fourth portion of the shuttertime/v from when the shutter has opened.

It can be assumed that the object corresponding to the foreground is arigid body, and the foreground object is moving with constant velocitysuch that it is displayed four pixels to the right in the subsequentframe. Accordingly, for example, the foreground component F04/v of theleft most pixel in FIG. 17 corresponding to the first portion of theshutter time/v from when the shutter has opened is equal to theforeground component of the second pixel from the left in FIG. 17corresponding to the second portion of the shutter time/v from when theshutter has opened. Similarly, the foreground component F04/v is equalto the foreground component of the third pixel from the left in FIG. 17corresponding to the third portion of the shutter time/v from when theshutter has opened, and the foreground component of the fourth pixelfrom the left in FIG. 17 corresponding to the fourth portion of theshutter time/v from when the shutter has opened.

Since the foreground area corresponding to the moving object containsmotion blur as discussed above, it can also be referred to as a“distortion area”.

FIG. 18 illustrates a model obtained by expanding in the time directionthe pixel values of the pixels in one line including an uncoveredbackground area when the object corresponding to the foreground ismoving to the right in FIG. 18. In FIG. 18, the amount of movement v is4. Since one frame is a short period, it can be assumed that the objectcorresponding to the foreground is a rigid body moving with constantvelocity. In FIG. 18, the object image corresponding to the foregroundis moving to the right such that it is positioned four pixels to theright with respect to a reference frame when it is displayed in thesubsequent frame.

In FIG. 18, the pixels from the leftmost pixel to the fourth pixelbelong to the background area. In FIG. 18, the pixels from the fifthpixel to the seventh pixels from the left belong to the mixed area,which is an uncovered background area. In FIG. 18, the rightmost pixelbelongs to the foreground area.

The object corresponding to the foreground which covers the objectcorresponding to the background is moving such that it is graduallyremoved from the object corresponding to the background over time.Accordingly, the components contained in the pixel values of the pixelsbelonging to the uncovered background area change from the foregroundcomponents to the background components at a certain time of the periodcorresponding to the shutter time.

For example, the pixel value M′ surrounded by the thick frame in FIG. 18is expressed by equation (2).M′=F02/v+F01/v+B26/v+B26/v  (2)

For example, the fifth pixel from the left contains backgroundcomponents corresponding to three portions of the shutter time/v and aforeground component corresponding to one shutter portion of the shuttertime/v, and thus, the mixture ratio α of the fifth pixel from the leftis ¾. The sixth pixel from the left contains background componentscorresponding to two portions of the shutter time/v and foregroundcomponents corresponding to two portions of the shutter time/v, andthus, the mixture ratio α of the sixth pixel from the left is ½. Theseventh pixel from the left contains a background componentcorresponding to one portion of the shutter time/v and foregroundcomponents corresponding to three portions of the shutter time/v, andthus, the mixture ratio α of the seventh pixel from the left is ¼.

When equations (1) and (2) are generalized, the pixel value M can beexpressed by equation (3):

$\begin{matrix}{M = {{\alpha \cdot B} + {\sum\limits_{i}{F\;{i/v}}}}} & (3)\end{matrix}$

where α is the mixture ratio, B indicates a pixel value of thebackground, and Fi/v designates a foreground component.

It can be assumed that the object corresponding to the foreground is arigid body, which is moving with constant velocity, and the amount ofmovement is 4. Accordingly, for example, the foreground component F01/vof the fifth pixel from the left in FIG. 18 corresponding to the firstportion of the shutter time/v from when the shutter has opened is equalto the foreground component of the sixth pixel from the left in FIG. 18corresponding to the second portion of the shutter time/v from when theshutter has opened. Similarly, the foreground component F01/v is equalto the foreground component of the seventh pixel from the left in FIG.18 corresponding to the third portion of the shutter time/v from whenthe shutter has opened, and the foreground component of the eighth pixelfrom the left in FIG. 18 corresponding to the fourth portion of theshutter time/v from when the shutter has opened.

It can be assumed that the object corresponding to the foreground is arigid body, which is moving with constant velocity, and the amount ofmovement v is 4. Accordingly, for example, the foreground componentF02/v of the sixth pixel from the left in FIG. 18 corresponding to thefirst portion of the shutter time/v from when the shutter has opened isequal to the foreground component of the seventh pixel from the left inFIG. 18 corresponding to the second portion of the shutter time/v fromwhen the shutter has opened. Similarly, the foreground component F02/vis equal to the foreground component of the eighth pixel from the leftin FIG. 18 corresponding to the third portion of the shutter time/v fromwhen the shutter has opened.

It can be assumed that the object corresponding to the foreground is arigid body, which is moving with constant velocity, and the amount ofmovement v is 4. Accordingly, for example, the foreground componentF03/v of the seventh pixel from the left in FIG. 18 corresponding to thefirst portion of the shutter time/v from when the shutter has opened isequal to the foreground component of the eighth pixel from the left inFIG. 18 corresponding to the second portion of the shutter time/v fromwhen the shutter has opened.

It has been described with reference to FIGS. 16 through 18 that thenumber of virtual divided portions is 4. The number of virtual dividedportions corresponds to the amount of movement v. Generally, the amountof movement v corresponds to the moving speed of the objectcorresponding to the foreground. For example, if the objectcorresponding to the foreground is moving such that it is displayed fourpixels to the right with respect to a certain frame when it ispositioned in the subsequent frame, the amount of movement v is set to4. The number of virtual divided portions is set to 4 in accordance withthe amount of movement v. Similarly, when the object corresponding tothe foreground is moving such that it is displayed six pixels to theleft with respect to a certain frame when it is positioned in thesubsequent frame, the amount of movement v is set to 6, and the numberof virtual divided portions is set to 6.

FIGS. 19 and 20 illustrate the relationship of the foreground area, thebackground area, and the mixed area which consists of a coveredbackground or an uncovered background, which are discussed above, to theforeground components and the background components corresponding to thedivided periods of the shutter time.

FIG. 19 illustrates an example in which pixels in the foreground area,the background area, and the mixed area are extracted from an imagecontaining a foreground corresponding to an object moving in front of astationary background. In the example shown in FIG. 19, an object Acorresponding to the foreground is horizontally moving with respect tothe screen.

Frame #n+1 is a frame subsequent to frame #n, and frame #n+2 is a framesubsequent to frame #n+1.

Pixels in the foreground area, the background area, and the mixed areaare extracted from one of frames #n through #n+2, and the amount ofmovement v is set to 4. A model obtained by expanding the pixel valuesof the extracted pixels in the time direction is shown in FIG. 20.

Since the object A corresponding to the foreground is moving, the pixelvalues in the foreground area are formed of four different foregroundcomponents corresponding to the shutter time/v. For example, theleftmost pixel of the pixels in the foreground area shown in FIG. 20consists of F01/v, F02/v, F03/v, and F04/v. That is, the pixels in theforeground contain motion blur.

Since the object corresponding to the background is stationary, lightinput into the sensor corresponding to the background during the shuttertime does not change. In this case, the pixel values in the backgroundarea do not contain motion blur.

The pixel values in the mixed area consisting of a covered backgroundarea or an uncovered background area are formed of foreground componentsand background components.

A description is given below of a model obtained by expanding in thetime direction the pixel values of the pixels which are alignedside-by-side in a plurality of frames and which are located at the samepositions when the frames are overlapped when the image corresponding tothe object is moving. For example, when the image corresponding to theobject is moving horizontally with respect to the screen, pixels alignedon the screen can be selected as the pixels aligned side-by-side.

FIG. 21 illustrates a model obtained by expanding in the time directionthe pixels which are aligned side-by-side in three frames of an imageobtained by capturing an object corresponding to a stationary backgroundand which are located at the same positions when the frames areoverlapped. Frame #n is the frame subsequent to frame #n−1, and frame#n+1 is the frame subsequent to frame #n. The same applies to the otherframes.

The pixel values B01 through B12 shown in FIG. 21 are pixel valuescorresponding to the stationary background object. Since the objectcorresponding to the background is stationary, the pixel values of thecorresponding pixels in frame #n−1 through frame #n+1 do not change. Forexample, the pixel in frame #n and the pixel in frame #n+1 located atthe corresponding position of the pixel having the pixel value B05 inframe #n−1 have the pixel value B05.

FIG. 22 illustrates a model obtained by expanding in the time directionthe pixels which are aligned side-by-side in three frames of an imageobtained by capturing an object corresponding to a foreground that ismoving to the right in FIG. 22 together with an object corresponding toa stationary background and which are located at the same positions whenthe frames are overlapped. The model shown in FIG. 22 contains a coveredbackground area.

In FIG. 22, it can be assumed that the object corresponding to theforeground is a rigid body moving with constant velocity, and that it ismoving such that it is displayed four pixels to the right in thesubsequent frame. Accordingly, the amount of movement v is 4, and thenumber of virtual divided portions is 4.

For example, the foreground component of the leftmost pixel of frame#n−1 in FIG. 22 corresponding to the first portion of the shutter time/vfrom when the shutter has opened is F12/v, and the foreground componentof the second pixel from the left in FIG. 22 corresponding to the secondportion of the shutter time/v from when the shutter has opened is alsoF12/v. The foreground component of the third pixel from the left in FIG.22 corresponding to the third portion of the shutter time/v from whenthe shutter has opened and the foreground component of the fourth pixelfrom the left in FIG. 22 corresponding to the fourth portion of theshutter time/v from when the shutter has opened are F12/v.

The foreground component of the leftmost pixel of frame #n−1 in FIG. 22corresponding to the second portion of the shutter time/v from when theshutter has opened is F11/v. The foreground component of the secondpixel from the left in FIG. 22 corresponding to the third portion of theshutter time/v from when the shutter has opened is also F11/v. Theforeground component of the third pixel from the left in FIG. 22corresponding to the fourth portion of the shutter time/v from when theshutter has opened is F11/v.

The foreground component of the leftmost pixel of frame #n−1 in FIG. 22corresponding to the third portion of the shutter time/v from when theshutter has opened is F10/v. The foreground component of the secondpixel from the left in FIG. 22 corresponding to the fourth portion ofthe shutter time/v from when the shutter has opened is also F10/v. Theforeground component of the leftmost pixel of frame #n−1 in FIG. 22corresponding to the fourth portion of the shutter time/v from when theshutter has opened is F09/v.

Since the object corresponding to the background is stationary, thebackground component of the second pixel from the left of frame #n−1 inFIG. 22 corresponding to the first portion of the shutter time/v fromwhen the shutter has opened is B01/v. The background components of thethird pixel from the left of frame #n−1 in FIG. 22 corresponding to thefirst and second portions of the shutter time/v from when the shutterhas opened are B02/v. The background components of the fourth pixel fromthe left of frame #n−1 in FIG. 22 corresponding to the first throughthird portions of the shutter time/v from when the shutter has openedare B03/v.

In frame #n−1 in FIG. 22, the leftmost pixel from the left belongs tothe foreground area, and the second through fourth pixels from the leftbelong to the mixed area, which is a covered background area.

The fifth through twelfth pixels from the left of frame #n−1 in FIG. 22belong to the background area, and the pixel values thereof are B04through B11, respectively.

The first through fifth pixels from the left in frame #n in FIG. 22belong to the foreground area. The foreground component in the shuttertime/v in the foreground area of frame #n is any one of F05/v throughF12/v.

It can be assumed that the object corresponding to the foreground is arigid body moving with constant velocity, and that it is moving suchthat the foreground image is displayed four pixels to the right in thesubsequent frame. Accordingly, the foreground component of the fifthpixel from the left of frame #n in FIG. 22 corresponding to the firstportion of the shutter time/v from when the shutter has opened is F12/v,and the foreground component of the sixth pixel from the left in FIG. 22corresponding to the second portion of the shutter time/v from when theshutter has opened is also F12/v. The foreground component of theseventh pixel from the left in FIG. 22 corresponding to the thirdportion of the shutter time/v from when the shutter has opened and theforeground component of the eighth pixel from the left in FIG. 22corresponding to the fourth portion of the shutter time/v from when theshutter has opened are F12/v.

The foreground component of the fifth pixel from the left of frame #n inFIG. 22 corresponding to the second portion of the shutter time/v fromwhen the shutter has opened is F11/v. The foreground component of thesixth pixel from the left in FIG. 22 corresponding to the third portionof the shutter time/v from when the shutter has opened is also F11/v.The foreground component of the seventh pixel from the left in FIG. 22corresponding to the fourth portion of the shutter time/v from when theshutter has opened is F11/v.

The foreground component of the fifth pixel from the left of frame #n inFIG. 22 corresponding to the third portion of the shutter time/v fromwhen the shutter has opened is F10/v. The foreground component of thesixth pixel from the left in FIG. 22 corresponding to the fourth portionof the shutter time/v from when the shutter has opened is also F10/v.The foreground component of the fifth pixel from the left of frame #n inFIG. 22 corresponding to the fourth portion of the shutter time/v fromwhen the shutter has opened is F09/v.

Since the object corresponding to the background is stationary, thebackground component of the sixth pixel from the left of frame #n inFIG. 22 corresponding to the first portion of the shutter time/v fromwhen the shutter has opened is B05/v. The background components of theseventh pixel from the left of frame #n in FIG. 22 corresponding to thefirst and second portions of the shutter time/v from when the shutterhas opened are B06/v. The background components of the eighth pixel fromthe left of frame #n in FIG. 22 corresponding to the first through thirdportion of the shutter time/v from when the shutter has opened areB07/v.

In frame #n in FIG. 22, the sixth through eighth pixels from the leftbelong to the mixed area, which is a covered background area.

The ninth through twelfth pixels from the left of frame #n in FIG. 22belong to the background area, and the pixel values thereof are B08through B11, respectively.

The first through ninth pixels from the left in frame #n+1 in FIG. 22belong to the foreground area. The foreground component in the shuttertime/v in the foreground area of frame #n+1 is any one of F01/v throughF12/v.

It can be assumed that the object corresponding to the foreground is arigid body moving with constant velocity, and that it is moving suchthat the foreground image is displayed four pixels to the right in thesubsequent frame. Accordingly, the foreground component of the ninthpixel from the left of frame #n+1 in FIG. 22 corresponding to the firstportion of the shutter time/v from when the shutter has opened is F12/v,and the foreground component of the tenth pixel from the left in FIG. 22corresponding to the second portion of the shutter time/v from when theshutter has opened is also F12/v. The foreground component of theeleventh pixel from the left in FIG. 22 corresponding to the thirdportion of the shutter time/v from when the shutter has opened and theforeground component of the twelfth pixel from the left in FIG. 22corresponding to the fourth portion of the shutter time/v from when theshutter has opened are F12/v.

The foreground component of the ninth pixel from the left of frame #n+1in FIG. 22 corresponding to the second portion of the shutter time/vfrom when the shutter has opened is F11/v. The foreground component ofthe tenth pixel from the left in FIG. 22 corresponding to the thirdportion of the shutter time/v from when the shutter has opened is alsoF11/v. The foreground component of the eleventh pixel from the left inFIG. 22 corresponding to the fourth portion of the shutter time/v fromwhen the shutter has opened is F11/v.

The foreground component of the ninth pixel from the left of frame #n+1in FIG. 22 corresponding to the third portion of the shutter time/v fromwhen the shutter has opened is F10/v. The foreground component of thetenth pixel from the left in FIG. 22 corresponding to the fourth portionof the shutter time/v from when the shutter has opened is also F10/v.The foreground component of the ninth pixel from the left of frame #n+1in FIG. 22 corresponding to the fourth portion of the shutter time/vfrom when the shutter has opened is F09/v.

Since the object corresponding to the background is stationary, thebackground component of the tenth pixel from the left of frame #n+1 inFIG. 22 corresponding to the first portion of the shutter time/v fromwhen the shutter has opened is B09/v. The background components of theeleventh pixel from the left of frame #n+1 in FIG. 22 corresponding tothe first and second portions of the shutter time/v from when theshutter has opened are B10/v. The background components of the twelfthpixel from the left of frame #n+1 in FIG. 22 corresponding to the firstthrough third portion of the shutter time/v from when the shutter hasopened are B11/v.

In frame #n+1 in FIG. 22, the tenth through twelfth pixels from the leftbelong to the mixed area, which is a covered background area.

FIG. 23 is a model of an image obtained by extracting the foregroundcomponents from the pixel values shown in FIG. 22.

FIG. 24 illustrates a model obtained by expanding in the time directionthe pixels which are aligned side-by-side in three frames of an imageobtained by capturing an object corresponding to a foreground that ismoving to the right in FIG. 24 together with an object corresponding toa stationary background and which are located at the same positions whenthe frames are overlapped. The model shown in FIG. 24 contains anuncovered background area.

In FIG. 24, it can be assumed that the object corresponding to theforeground is a rigid body moving with constant velocity, and that it ismoving such that it is displayed four pixels to the right in thesubsequent frame. Accordingly, the amount of movement v is 4.

For example, the foreground component of the leftmost pixel of frame#n−1 in FIG. 24 corresponding to the first portion of the shutter time/vfrom when the shutter has opened is F13/v, and the foreground componentof the second pixel from the left in FIG. 24 corresponding to the secondportion of the shutter time/v from when the shutter has opened is alsoF13/v. The foreground component of the third pixel from the left in FIG.24 corresponding to the third portion of the shutter time/v from whenthe shutter has opened and the foreground component of the fourth pixelfrom the left in FIG. 24 corresponding to the fourth portion of theshutter time/v from when the shutter has opened are F13/v.

The foreground component of the second pixel from the left of frame #n−1in FIG. 24 corresponding to the first portion of the shutter time/v fromwhen the shutter has opened is F14/v. The foreground component of thethird pixel from the left in FIG. 24 corresponding to the second portionof the shutter time/v from when the shutter has opened is also F14/v.The foreground component of the third pixel from the left in FIG. 24corresponding to the first portion of the shutter time/v from when theshutter has opened is F15/v.

Since the object corresponding to the background is stationary, thebackground components of the leftmost pixel of frame #n−1 in FIG. 24corresponding to the second through fourth portions of the shuttertime/v from when the shutter has opened are B25/v. The backgroundcomponents of the second pixel from the left of frame #n−1 in FIG. 24corresponding to the third and fourth portions of the shutter time/vfrom when the shutter has opened are B26/v. The background component ofthe third pixel from the left of frame #n−1 in FIG. 24 corresponding tothe fourth portion of the shutter time/v from when the shutter hasopened is B27/v.

In frame #n−1 in FIG. 24, the leftmost pixel through the third pixelbelong to the mixed area, which is an uncovered background area.

The fourth through twelfth pixels from the left of frame #n−1 in FIG. 24belong to the foreground area. The foreground component of the frame isany one of F13/v through F24/v.

The leftmost pixel through the fourth pixel from the left of frame #n inFIG. 24 belong to the background area, and the pixel values thereof areB25 through B28, respectively.

It can be assumed that the object corresponding to the foreground is arigid body moving with constant velocity, and that it is moving suchthat it is displayed four pixels to the right in the subsequent frame.Accordingly, the foreground component of the fifth pixel from the leftof frame #n in FIG. 24 corresponding to the first portion of the shuttertime/v from when the shutter has opened is F13/v, and the foregroundcomponent of the sixth pixel from the left in FIG. 24 corresponding tothe second portion of the shutter time/v from when the shutter hasopened is also F13/v. The foreground component of the seventh pixel fromthe left in FIG. 24 corresponding to the third portion of the shuttertime/v from when the shutter has opened and the foreground component ofthe eighth pixel from the left in FIG. 24 corresponding to the fourthportion of the shutter time/v from when the shutter has opened areF13/v.

The foreground component of the sixth pixel from the left of frame #n inFIG. 24 corresponding to the first portion of the shutter time/v fromwhen the shutter has opened is F14/v. The foreground component of theseventh pixel from the left in FIG. 24 corresponding to the secondportion of the shutter time/v from when the shutter has opened is alsoF14/v. The foreground component of the eighth pixel from the left inFIG. 24 corresponding to the first portion of the shutter time/v fromwhen the shutter has opened is F15/v.

Since the object corresponding to the background is stationary, thebackground components of the fifth pixel from the left of frame #n inFIG. 24 corresponding to the second through fourth portions of theshutter time/v from when the shutter has opened are B29/v. Thebackground components of the sixth pixel from the left of frame #n inFIG. 24 corresponding to the third and fourth portions of the shuttertime/v from when the shutter has opened are B30/v. The backgroundcomponent of the seventh pixel from the left of frame #n in FIG. 24corresponding to the fourth portion of the shutter time/v from when theshutter has opened is B31/v.

In frame #n in FIG. 24, the fifth pixel through the seventh pixel fromthe left belong to the mixed area, which is an uncovered backgroundarea.

The eighth through twelfth pixels from the left of frame #n in FIG. 24belong to the foreground area. The value in the foreground area of frame#n corresponding to the period of the shutter time/v is any one of F13/vthrough F20/v.

The leftmost pixel through the eighth pixel from the left of frame #n+1in FIG. 24 belong to the background area, and the pixel values thereofare B25 through B32, respectively.

It can be assumed that the object corresponding to the foreground is arigid body moving with constant velocity, and that it is moving suchthat it is displayed four pixels to the right in the subsequent frame.Accordingly, the foreground component of the ninth pixel from the leftof frame #n+1 in FIG. 24 corresponding to the first portion of theshutter time/v from when the shutter has opened is F13/v, and theforeground component of the tenth pixel from the left in FIG. 24corresponding to the second portion of the shutter time/v from when theshutter has opened is also F13/v. The foreground component of theeleventh pixel from the left in FIG. 24 corresponding to the thirdportion of the shutter time/v from when the shutter has opened and theforeground component of the twelfth pixel from the left in FIG. 24corresponding to the fourth portion of the shutter time/v from when theshutter has opened are F13/v.

The foreground component of the tenth pixel from the left of frame #n+1in FIG. 24 corresponding to the first portion of the shutter time/v fromwhen the shutter has opened is F14/v. The foreground component of theeleventh pixel from the left in FIG. 24 corresponding to the secondportion of the shutter time/v from when the shutter has opened is alsoF14/v. The foreground component of the twelfth pixel from the left inFIG. 24 corresponding to the first portion of the shutter time/v fromwhen the shutter has opened is F15/v.

Since the object corresponding to the background is stationary, thebackground components of the ninth pixel from the left of frame #n+1 inFIG. 24 corresponding to the second through fourth portions of theshutter time/v from when the shutter has opened are B33/v. Thebackground components of the tenth pixel from the left of frame #n+1 inFIG. 24 corresponding to the third and fourth portions of the shuttertime/v from when the shutter has opened are B34/v. The backgroundcomponent of the eleventh pixel from the left of frame #n+1 in FIG. 24corresponding to the fourth portion of the shutter time/v from when theshutter has opened is B35/v.

In frame #n+1 in FIG. 24, the ninth through eleventh pixels from theleft in FIG. 24 belong to the mixed area, which is an uncoveredbackground area.

The twelfth pixel from the left of frame #n+1 in FIG. 24 belongs to theforeground area. The foreground component in the shutter time/v in theforeground area of frame #n+1 is any one of F13 through F16,respectively.

FIG. 25 illustrates a model of an image obtained by extracting theforeground components from the pixel values shown in FIG. 24.

Referring back to FIG. 9, the area specifying unit 103 specifies flagsindicating to which of a foreground area, a background area, a coveredbackground area, or an uncovered background area the individual pixelsof the input image belong by using the pixel values of a plurality offrames, and supplies the flags to the mixture-ratio calculator 104 andthe motion-blur adjusting unit 106 as the area information.

The mixture-ratio calculator 104 calculates the mixture ratio α for eachpixel contained in the mixed area based on the pixel values of aplurality of frames and the area information, and supplies thecalculated mixture ratio α to the foreground/background separator 105.

The foreground/background separator 105 extracts the foregroundcomponent image consisting of only the foreground components based onthe pixel values of a plurality of frames, the area information, and themixture ratio α, and supplies the foreground component image to themotion-blur adjusting unit 106.

The motion-blur adjusting unit 106 adjusts the amount of motion blurcontained in the foreground component image based on the foregroundcomponent image supplied from the foreground/background separator 105,the motion vector supplied from the motion detector 102, and the areainformation supplied from the area specifying unit 103, and then outputsthe foreground component image in which motion blur is adjusted.

The processing for adjusting the amount of motion blur performed by theseparating portion 91 is described below with reference to the flowchartof FIG. 26. In step S11, the area specifying unit 103 executes areaspecifying processing, based on an input image, for generating areainformation indicating to which of a foreground area, a background area,a covered background area, or an uncovered background area each pixel ofthe input image belongs. Details of the area specifying processing aregiven below. The area specifying unit 103 supplies the generated areainformation to the mixture-ratio calculator 104.

In step S11, the area specifying unit 103 may generate, based on theinput image, area information indicating to which of the foregroundarea, the background area, or the mixed area (regardless of whether eachpixel belongs to a covered background area or an uncovered backgroundarea) each pixel of the input image belongs. In this case, theforeground/background separator 105 and the motion-blur adjusting unit106 determine based on the direction of the motion vector whether themixed area is a covered background area or an uncovered background area.For example, if the input image is disposed in the order of theforeground area, the mixed area, and the background area in thedirection of the motion vector, it is determined that the mixed area isa covered background area. If the input image is disposed in the orderof the background area, the mixed area, and the foreground area in thedirection of the motion vector, it is determined that the mixed area isan uncovered background area.

In step S12, the mixture-ratio calculator 104 calculates the mixtureratio α for each pixel contained in the mixed area based on the inputimage and the area information. Details of the mixture ratio calculatingprocessing are given below. The mixture-ratio calculator 104 suppliesthe calculated mixture ratio α to the foreground/background separator105.

In step S13, the foreground/background separator 105 extracts theforeground components from the input image based on the area informationand the mixture ratio α, and supplies the foreground components to themotion-blur adjusting unit 106 as the foreground component image.

In step S14, the motion-blur adjusting unit 106 generates, based on themotion vector and the area information, the unit of processing thatindicates the positions of consecutive pixels disposed in the movingdirection and belonging to any of the uncovered background area, theforeground area, and the covered background area, and adjusts the amountof motion blur contained in the foreground components corresponding tothe unit of processing. Details of the processing for adjusting theamount of motion blur are given below.

In step S15, the separating portion 91 determines whether the processingis finished for the whole screen. If it is determined, that theprocessing is not finished for the whole screen, the process proceeds tostep S14, and the processing for adjusting the amount of motion blur forthe foreground components corresponding to the unit of processing isrepeated.

If it is determined in step S15 that the processing is finished for thewhole screen, the processing is completed.

In this manner, the separating portion 91 is capable of adjusting theamount of motion blur contained in the foreground by separating theforeground and the background. That is, the separating portion 91 iscapable of adjusting the amount of motion blur contained in sampled dataindicating the pixel values of the foreground pixels.

The configuration of each of the area specifying unit 103, themixture-ratio calculator 104, the foreground/background separator 105,and the motion-blur adjusting unit 106 is described below.

FIG. 27 is a block diagram illustrating an example of the configurationof the area specifying unit 103. The area specifying unit 103 shown inFIG. 27 does not use a motion vector. A frame memory 201 stores an inputimage in units of frames. When the image to be processed is frame #n,the frame memory 201 stores frame #n−2, which is the frame two framesbefore frame #n, frame #n−1, which is the frame one frame before frame#n, frame #n, frame #n+1, which is the frame one frame after frame #n,frame #n+2, which is the frame two frames after frame #n.

A stationary/moving determining portion 202-1 reads the pixel value ofthe pixel of frame #n+2 located at the same position as a designatedpixel of frame #n in which the area to which the pixel belongs isdetermined, and reads the pixel value of the pixel of frame #n+1 locatedat the same position of the designated pixel of frame #n from the framememory 201, and calculates the absolute value of the difference betweenthe read pixel values. The stationary/moving determining portion 202-1determines whether the absolute value of the difference between thepixel value of frame #n+2 and the pixel value of frame #n+1 is greaterthan a preset threshold Th. If it is determined that the difference isgreater than the threshold Th, a stationary/moving determinationindicating “moving” is supplied to an area determining portion 203-1. Ifit is determined that the absolute value of the difference between thepixel value of the pixel of frame #n+2 and the pixel value of the pixelof frame #n+1 is smaller than or equal to the threshold Th, thestationary/moving determining portion 202-1 supplies a stationary/movingdetermination indicating “stationary” to the area determining portion203-1.

A stationary/moving determining portion 202-2 reads the pixel value of adesignated pixel of frame #n in which the area to which the pixelbelongs is determined, and reads the pixel value of the pixel of frame#n+1 located at the same position as the designated pixel of frame #nfrom the frame memory 201, and calculates the absolute value of thedifference between the pixel values. The stationary/moving determiningportion 202-2 determines whether the absolute value of the differencebetween the pixel value of frame #n+1 and the pixel value of frame #n isgreater than a preset threshold Th. If it is determined that theabsolute value of the difference between the pixel values is greaterthan the threshold Th, a stationary/moving determination indicating“moving” is supplied to the area determining portion 203-1 and an areadetermining portion 203-2. If it is determined that the absolute valueof the difference between the pixel value of the pixel of frame #n+1 andthe pixel value of the pixel of frame #n is smaller than or equal to thethreshold Th, the stationary/moving determining portion 202-2 supplies astationary/moving determination indicating “stationary” to the areadetermining portion 203-1 and the area determining portion 203-2.

A stationary/moving determining portion 202-3 reads the pixel value of adesignated pixel of frame #n in which the area to which the pixelbelongs is determined, and reads the pixel value of the pixel of frame#n−1 located at the same position as the designated pixel of frame #nfrom the frame memory 201, and calculates the absolute value of thedifference between the pixel values. The stationary/moving determiningportion 202-3 determines whether the absolute value of the differencebetween the pixel value of frame #n and the pixel value of frame #n−1 isgreater than a preset threshold Th. If it is determined that theabsolute value of the difference between the pixel values is greaterthan the threshold Th, a stationary/moving determination indicating“moving” is supplied to the area determining portion 203-2 and an areadetermining portion 203-3. If it is determined that the absolute valueof the difference between the pixel value of the pixel of frame #n andthe pixel value of the pixel of frame #n−1 is smaller than or equal tothe threshold Th, the stationary/moving determining portion 202-3supplies a stationary/moving determination indicating “stationary” tothe area determining portion 203-2 and the area determining portion203-3.

A stationary/moving determining portion 202-4 reads the pixel value ofthe pixel of frame #n−1 located at the same position as a designatedpixel of frame #n in which the area to which the pixel belongs isdetermined, and reads the pixel value of the pixel of frame #n−2 locatedat the same position as the designated pixel of frame #n from the framememory 201, and calculates the absolute value of the difference betweenthe pixel values. The stationary/moving determining portion 202-4determines whether the absolute value of the difference between thepixel value of frame #n−1 and the pixel value of frame #n−2 is greaterthan a preset threshold Th. If it is determined that the absolute valueof the difference between the pixel values is greater than the thresholdTh, a stationary/moving determination indicating “moving” is supplied tothe area determining portion 203-3. If it is determined that theabsolute value of the difference between the pixel value of the pixel offrame #n−1 and the pixel value of the pixel of frame #n−2 is smallerthan or equal to the threshold Th, the stationary/moving determiningportion 202-4 supplies a stationary/moving determination indicating“stationary” to the area determining portion 203-3.

When the stationary/moving determination supplied from thestationary/moving determining portion 202-1 indicates “stationary” andwhen the stationary/moving determination supplied from thestationary/moving determining portion 202-2 indicates “moving”, the areadetermining portion 203-1 determines that the designated pixel of frame#n belongs to an uncovered background area, and sets “1”, whichindicates that the designated pixel belongs to an uncovered backgroundarea, in an uncovered-background-area determining flag associated withthe designated pixel.

When the stationary/moving determination supplied from thestationary/moving determining portion 202-1 indicates “moving” or whenthe stationary/moving determination supplied from the stationary/movingdetermining portion 202-2 indicates “stationary”, the area specifyingunit 203-1 determines that the designated pixel of frame #n does notbelong to an uncovered background area, and sets “0”, which indicatesthat the designated pixel does not belong to an uncovered backgroundarea, in the uncovered-background-area determining flag associated withthe designated pixel.

The area determining portion 203-1 supplies theuncovered-background-area determining flag in which “1” or “0” is set asdiscussed above to a determining-flag-storing frame memory 204.

When the stationary/moving determination supplied from thestationary/moving determining portion 202-2 indicates “stationary” andwhen the stationary/moving determination supplied from thestationary/moving determining portion 202-3 indicate “stationary”, thearea determining portion 203-2 determines that the designated pixel offrame #n belongs to the stationary area, and sets “1”, which indicatesthat the pixel belongs to the stationary area, in a stationary-areadetermining flag associated with the designated pixel.

When the stationary/moving determination supplied from thestationary/moving determining portion 202-2 indicates “moving” or whenthe stationary/moving determination supplied from the stationary/movingdetermining portion 202-3 indicate “moving”, the area determiningportion 203-2 determines that the designated pixel of frame #n does notbelong to the stationary area, and sets “0”, which indicates that thepixel does not belong to the stationary area, in the stationary-areadetermining flag associated with the designated pixel.

The area determining portion 203-2 supplies the stationary-areadetermining flag in which “1” or “0” is set as discussed above to thedetermining-flag-storing frame memory 204.

When the stationary/moving determination supplied from thestationary/moving determining portion 202-2 indicates “moving” and whenthe stationary/moving determination supplied from the stationary/movingdetermining portion 202-3 indicate “moving”, the area determiningportion 203-2 determines that the designated pixel of frame #n belongsto the moving area, and sets “1”, which indicates that the designatedpixel belongs to the moving area, in a moving-area determining flagassociated with the designated pixel.

When the stationary/moving determination supplied from thestationary/moving determining portion 202-2 indicates “stationary” orwhen the stationary/moving determination supplied from thestationary/moving determining portion 202-3 indicate “stationary”, thearea determining portion 203-2 determines that the designated pixel offrame #n does not belong to the moving area, and sets “0”, whichindicates that the pixel does not belong to the moving area, in themoving-area determining flag associated with the designated pixel.

The area determining portion 203-2 supplies the moving-area determiningflag in which “1” or “0” is set as discussed above to thedetermining-flag-storing frame memory 204.

When the stationary/moving determination supplied from thestationary/moving determining portion 202-3 indicates “moving” and whenthe stationary/moving determination supplied from the stationary/movingdetermining portion 202-4 indicate “stationary”, the area determiningportion 203-3 determines that the designated pixel of frame #n belongsto a covered background area, and sets “1”, which indicates that thedesignated pixel belongs to the covered background area, in acovered-background-area determining flag associated with the designatedpixel.

When the stationary/moving determination supplied from thestationary/moving determining portion 202-3 indicates “stationary” orwhen the stationary/moving determination supplied from thestationary/moving determining portion 202-4 indicate “moving”, the areadetermining portion 203-3 determines that the designated pixel of frame#n does not belong to a covered background area, and sets “0”, whichindicates that the designated pixel does not belong to a coveredbackground area, in the covered-background-area determining flagassociated with the designated pixel.

The area determining portion 203-3 supplies the covered-background-areadetermining flag in which “1” or “0” is set as discussed above to thedetermining-flag-storing frame memory 204.

The determining-flag-storing frame memory 204 thus stores theuncovered-background-area determining flag supplied from the areadetermining portion 203-1, the stationary-area determining flag suppliedfrom the area determining portion 203-2, the moving-area determiningflag supplied from the area determining portion 203-2, and thecovered-background-area determining flag supplied from the areadetermining portion 203-3.

The determining-flag-storing frame memory 204 supplies theuncovered-background-area determining flag, the stationary-areadetermining flag, the moving-area determining flag, and thecovered-background-area determining flag stored therein to a synthesizer205. The synthesizer 205 generates area information indicating to whichof the uncovered background area, the stationary area, the moving area,or the covered background area each pixel belongs based on theuncovered-background-area determining flag, the stationary-areadetermining flag, the moving-area determining flag, and thecovered-background-area determining flag supplied from thedetermining-flag-storing frame memory 204, and supplies the areainformation to a determining-flag-storing frame memory 206.

The determining-flag-storing frame memory 206 stores the areainformation supplied from the synthesizer 205, and also outputs the areainformation stored therein.

An example of the processing performed by the area specifying unit 103is described below with reference to FIGS. 28 through 32.

When the object corresponding to the foreground is moving, the positionof the image corresponding to the object on the screen changes in everyframe. As shown in FIG. 28, the image corresponding to the objectlocated at the position indicated by Yn(x,y) in frame #n is positionedat Yn+1(x,y) in frame #n+1, which is subsequent to frame #n.

A model obtained by expanding in the time direction the pixel values ofthe pixels aligned side-by-side in the moving direction of the imagecorresponding to the foreground object is shown in FIG. 22. For example,if the moving direction of the image corresponding to the foregroundobject is horizontal with respect to the screen, the model shown in FIG.29 is a model obtained by expanding in the time direction the pixelvalues of the pixels disposed on a line side-by-side.

In FIG. 29, the line in frame #n is equal to the line in frame #n+1.

The foreground components corresponding to the object contained in thesecond pixel to the thirteenth pixel from the left in frame #n arecontained in the sixth pixel through the seventeenth pixel from the leftin frame #n+1.

In frame #n, the pixels belonging to the covered background area are theeleventh through thirteenth pixels from the left, and the pixelsbelonging to the uncovered background area are the second through fourthpixels from the left. In frame #n+1, the pixels belonging to the coveredbackground area are the fifteenth through seventeenth pixels from theleft, and the pixels belonging to the uncovered background area are thesixth through eighth pixels from the left.

In the example shown in FIG. 29, since the foreground componentscontained in frame #n are moved by four pixels in frame #n+1, the amountof movement v is 4. The number of virtual divided portions is 4 inaccordance with the amount of movement v.

A description is now given of a change in pixel values of the pixelsbelonging to the mixed area in the frames before and after a designatedframe.

In FIG. 30, the pixels belonging to a covered background area in frame#n in which the background is stationary and the amount of movement v inthe foreground is 4 are the fifteenth through seventeenth pixels fromthe left. Since the amount of movement v is 4, the fifteenth throughseventeenth frames from the left in the previous frame #n−1 contain onlybackground components and belong to the background area. The fifteenththrough seventeenth pixels from the left in frame #n−2, which is onebefore frame #n−1, contain only background components and belong to thebackground area.

Since the object corresponding to the background is stationary, thepixel value of the fifteenth pixel from the left in frame #n−1 does notchange from the pixel value of the fifteenth pixel from the left inframe #n−2. Similarly, the pixel value of the sixteenth pixel from theleft in frame #n−1 does not change from the pixel value of the sixteenthpixel from the left in frame #n−2, and the pixel value of theseventeenth pixel from the left in frame #n−1 does not change from thepixel value of the seventeenth pixel from the left in frame #n−2.

That is, the pixels in frame #n−1 and frame #n−2 corresponding to thepixels belonging to the covered background area in frame #n consist ofonly background components, and the pixel values thereof do not change.Accordingly, the absolute value of the difference between the pixelvalues is almost 0. Thus, the stationary/moving determination made forthe pixels in frame #n−1 and frame #n−2 corresponding to the pixelsbelonging to the mixed area in frame #n by the stationary/movingdetermining portion 202-4 is “stationary”.

Since the pixels belonging to the covered background area in frame #ncontain foreground components, the pixel values thereof are differentfrom those of frame #n−1 consisting of only background components.Accordingly, the stationary/moving determination made for the pixelsbelonging to the mixed area in frame #n and the corresponding pixels inframe #n−1 by the stationary/moving determining portion 202-3 is“moving”.

When the stationary/moving determination result indicating “moving” issupplied from the stationary/moving determining portion 202-3, and whenthe stationary/moving determination result indicating “stationary” issupplied from the stationary/moving determining portion 202-4, asdiscussed above, the area determining portion 203-3 determines that thecorresponding pixels belong to a covered background area.

In FIG. 31, in frame #n in which the background is stationary and theamount of movement v in the foreground is 4, the pixels contained in anuncovered background area are the second through fourth pixels from theleft. Since the amount of movement v is 4, the second through fourthpixels from the left in the subsequent frame #n+1 contain onlybackground components and belong to the background area. In frame #n+2,which is subsequent to frame #n+1, the second through fourth pixels fromthe left contain only background components and belong to the backgroundarea.

Since the object corresponding to the background is stationary, thepixel value of the second pixel from the left in frame #n+2 does notchange from the pixel value of the second pixel from the left in frame#n+1. Similarly, the pixel value of the third pixel from the left inframe #n+2 does not change from the pixel value of the third pixel fromthe left in frame #n+1, and the pixel value of the fourth pixel from theleft in frame #n+2 does not change from the pixel value of the fourthpixel from the left in frame #n+1.

That is, the pixels in frame #n+1 and frame #n+2 corresponding to thepixels belonging to the uncovered background area in frame #n consist ofonly background components, and the pixel values thereof do not change.Accordingly, the absolute value of the difference between the pixelvalues is almost 0. Thus, the stationary/moving determination made forthe pixels in frame #n+1 and frame #n+2 corresponding to the pixelsbelonging to the mixed area in frame #n by the stationary/movingdetermining portion 202-1 is “stationary”.

Since the pixels belonging to the uncovered background area in frame #ncontain foreground components, the pixel values thereof are differentfrom those of frame #n+1 consisting of only background components.Accordingly, the stationary/moving determination made for the pixelsbelonging to the mixed area in frame #n and the corresponding pixels inframe #n+1 by the stationary/moving determining portion 202-2 is“moving”.

When the stationary/moving determination result indicating “moving” issupplied from the stationary/moving determining portion 202-2, and whenthe stationary/moving determination result indicating “stationary” issupplied from the stationary/moving determining portion 202-1, asdiscussed above, the area determining portion 203-1 determines that thecorresponding pixels belong to an uncovered background area.

FIG. 32 illustrates determination conditions for frame #n made by thearea specifying unit 103. When the determination result for the pixel inframe #n−2 located at the same image position as a pixel in frame #n tobe processed and for the pixel in frame #n−1 located at the sameposition as the pixel in frame #n is stationary, and when thedetermination result for the pixel in frame #n and the pixel in frame#n−1 located at the same image position as the pixel in frame #n ismoving, the area specifying unit 103 determines that the pixel in frame#n belongs to a covered background area.

When the determination result for the pixel in frame #n and the pixel inframe #n−1 located at the same image position as the pixel in frame #nis stationary, and when the determination result for the pixel in frame#n and the pixel in frame #n+1 located at the same image position as thepixel in frame #n is stationary, the area specifying unit 103 determinesthat the pixel in frame #n belongs to the stationary area.

When the determination result for the pixel in frame #n and the pixel inframe #n−1 located at the same image position as the pixel in frame #nis moving, and when the determination result for the pixel in frame #nand the pixel in frame #n+1 located at the same image position as thepixel in frame #n is moving, the area specifying unit 103 determinesthat the pixel in frame #n belongs to the moving area.

When the determination result for the pixel in frame #n and the pixel inframe #n+1 located at the same image position as the pixel in frame #nis moving, and when the determination result for the pixel in frame #n+1located at the same image position as the pixel in frame #n and thepixel in frame #n+2 located at the same image position as the pixel inframe #n is stationary, the area specifying unit 103 determines that thepixel in frame #n belongs to an uncovered background area.

FIGS. 33A through 33D illustrate examples of the area determinationresults obtained by the area specifying unit 103. In FIG. 33A, thepixels which are determined to belong to a covered background area areindicated in white. In FIG. 33B, the pixels which are determined tobelong to an uncovered background area are indicated in white.

In FIG. 33C, the pixels which are determined to belong to a moving areaare indicated in white. In FIG. 33D, the pixels which are determined tobelong to a stationary area are indicated in white.

FIG. 34 illustrates the area information indicating the mixed area, inthe form of an image, selected from the area information output from thedetermining-flag-storing frame memory 206. In FIG. 34, the pixels whichare determined to belong to the covered background area or the uncoveredbackground area, i.e., the pixels which are determined to belong to themixed area, are indicated in white. The area information indicating themixed area output from the determining-flag-storing frame memory 206designates the mixed area and the portions having a texture surroundedby the portions without a texture in the foreground area.

The area specifying processing performed by the area specifying unit 103is described below with reference to the flowchart of FIG. 35. In stepS201, the frame memory 201 obtains an image of frame #n−2 through frame#n+2 including frame #n.

In step S202, the stationary/moving determining portion 202-3 determineswhether the determination result for the pixel in frame #n−1 and thepixel in frame #n located at the same position is stationary. If it isdetermined that the determination result is stationary, the processproceeds to step S203 in which the stationary/moving determining portion202-2 determines whether the determination result for the pixel in frame#n and the pixel in frame #n+1 located at the same position isstationary.

If it is determined in step S203 that the determination result for thepixel in frame #n and the pixel in frame #n+1 located at the sameposition is stationary, the process proceeds to step S204. In step S204,the area determining portion 203-2 sets “1”, which indicates that thepixel to be processed belongs to the stationary area, in thestationary-area determining flag associated with the pixel to beprocessed. The area determining portion 203-2 supplies thestationary-area determining flag to the determining-flag-storing framememory 204, and the process proceeds to step S205.

If it is determined in step S202 that the determination result for thepixel in frame #n−1 and the pixel in frame #n located at the sameposition is moving, or if it is determined in step S203 that thedetermination result for the pixel in frame #n and the pixel in frame#n+1 located at the same position is moving, the pixel to be processeddoes not belong to a stationary area. Accordingly, the processing ofstep S204 is skipped, and the process proceeds to step S205.

In step S205, the stationary/moving determining portion 202-3 determineswhether the determination result for the pixel in frame #n−1 and thepixel in frame #n located at the same position is moving. If it isdetermined that the determination result is moving, the process proceedsto step S206 in which the stationary/moving determining portion 202-2determines whether the determination result for the pixel in frame #nand the pixel in frame #n+1 located at the same position is moving.

If it is determined in step S206 that the determination result for thepixel in frame #n and the pixel in frame #n+1 located at the sameposition is moving, the process proceeds to step S207. In step S207, thearea determining portion 203-2 sets “1”, which indicates that the pixelto be processed belongs to a moving area, in the moving-area determiningflag associated with the pixel to be processed. The area determiningarea 203-2 supplies the moving-area determining flag to thedetermining-flag-storing frame memory 204, and the process proceeds tostep S208.

If it is determined in step S205 that the determination result for thepixel in frame #n−1 and the pixel in frame #n located at the sameposition is stationary, or if it is determined in step S206 that thedetermination result for the pixel in frame #n and the pixel in frame#n+1 located at the same position is stationary, the pixel in frame #ndoes not belong to a moving area. Accordingly, the processing of stepS207 is skipped, and the process proceeds to step S208.

In step S208, the stationary/moving determining portion 202-4 determineswhether the determination result for the pixel in frame #n−2 and thepixel in frame #n−1 located at the same position is stationary. If it isdetermined that the determination result is stationary, the processproceeds to step S209 in which the stationary/moving determining portion202-3 determines whether the determination result for the pixel in frame#n−1 and the pixel in frame #n located at the same position is moving.

If it is determined in step S209 that the determination result for thepixel in frame #n−1 and the pixel in frame #n located at the sameposition is moving, the process proceeds to step S210. In step S210, thearea determining portion 203-3 sets “1”, which indicates that the pixelto be processed belongs to a covered background area, in thecovered-background-area determining flag associated with the pixel to beprocessed. The area determining portion 203-3 supplies thecovered-background-area determining flag to the determining-flag-storingframe memory 204, and the process proceeds to step S211. The areadetermining portion 203-3 supplies the covered-background-areadetermining flag to the determining-flag-storing frame memory 204, andthe process proceeds to step S211.

If it is determined in step S208 that the determination result for thepixel in frame #n−2 and the pixel in frame #n−1 located at the sameposition is moving, or if it is determined in step S209 that the pixelin frame #n−1 and the pixel in frame #n located at the same position isstationary, the pixel in frame #n does not belong to a coveredbackground area. Accordingly, the processing of step S210 is skipped,and the process proceeds to step S211.

In step S211, the stationary/moving determining portion 202-2 determineswhether the determination result for the pixel in frame #n and the pixelin frame #n+1 located at the same position is moving. If it isdetermined in step S211 that the determination result is moving, theprocess proceeds to step S212 in which the stationary/moving determiningportion 202-1 determines whether the determination result for the pixelin frame #n+1 and the pixel in frame #n+2 located at the same positionis stationary.

If it is determined in step S212 that the determination result for thepixel in frame #n+1 and the pixel in frame #n+2 located at the sameposition is stationary, the process proceeds to step S213. In step S213,the area determining portion 203-1 sets “1”, which indicates that thepixel to be processed belongs to an uncovered background area, in theuncovered-background-area determining flag associated with the pixel tobe processed. The area determining portion 203-1 supplies theuncovered-background-flag determining flag to thedetermining-flag-storing frame memory 204, and the process proceeds tostep S214.

If it is determined in step S211 that the determination result for thepixel in frame #n and the pixel in frame #n+1 located at the sameposition is stationary, or if it is determined in step S212 that thedetermination result for the pixel in frame #n+1 and the pixel in frame#n+2 is moving, the pixel in frame #n does not belong to an uncoveredbackground area. Accordingly, the processing of step S213 is skipped,and the process proceeds to step S214.

In step S214, the area specifying unit 103 determines whether the areasof all the pixels in frame #n are specified. If it is determined thatthe areas of all the pixels in frame #n are not yet specified, theprocess returns to step S202, and the area specifying processing isrepeated for the remaining pixels.

If it is determined in step S214 that the areas of all the pixels inframe #n are specified, the process proceeds to step S215. In step S215,the synthesizer 215 generates area information indicating the mixed areabased on the uncovered-background-area determining flag and thecovered-background-area determining flag stored in thedetermining-flag-storing frame memory 204, and also generates areainformation indicating to which of the uncovered background area, thestationary area, the moving area, or the covered background area eachpixel belongs, and sets the generated area information in thedetermining-flag-storing frame memory 206. The processing is thencompleted.

As discussed above, the area specifying unit 103 is capable ofgenerating area information indicating to which of the moving area, thestationary area, the uncovered background area, or the coveredbackground area each of the pixels contained in a frame belongs.

The area specifying unit 103 may apply logical OR to the areainformation corresponding to the uncovered background area and the areainformation corresponding to the covered background area so as togenerate area information corresponding to the mixed area, and then maygenerate area information consisting of flags indicating to which of themoving area, the stationary area, or the mixed area the individualpixels contained in the frame belong.

When the object corresponding to the foreground has a texture, the areaspecifying unit 103 is able to specify the moving area more precisely.

The area specifying unit 103 is able to output the area informationindicating the moving area as the area information indicating theforeground area, and outputs the area information indicating thestationary area as the area information indicating the background area.

The embodiment has been described, assuming that the objectcorresponding to the background is stationary. However, theabove-described area specifying processing can be applied even if theimage corresponding to the background area contains motion. For example,if the image corresponding to the background area is uniformly moving,the area specifying unit 103 shifts the overall image in accordance withthis motion, and performs processing in a manner similar to the case inwhich the object corresponding to the background is stationary. If theimage corresponding to the background area contains locally differentmotions, the area specifying unit 103 selects the pixels correspondingto the motions, and executes the above-described processing.

FIG. 36 is a block diagram illustrating another example of theconfiguration of the area specifying unit 103. The area specifying unit103 shown in FIG. 36 does not use a motion vector. A background imagegenerator 301 generates a background image corresponding to an inputimage, and supplies the generated background image to abinary-object-image extracting portion 302. The background imagegenerator 301 extracts, for example, an image object corresponding to abackground object contained in the input image, and generates thebackground image.

An example of a model obtained by expanding in the time direction thepixel values of pixels aligned side-by-side in the moving direction ofan image corresponding to a foreground object is shown in FIG. 37. Forexample, if the moving direction of the image corresponding to theforeground object is horizontal with respect to the screen, the modelshown in FIG. 37 is a model obtained by expanding the pixel values ofpixels disposed side-by-side on a single line in the time domain.

In FIG. 37, the line in frame #n is the same as the line in frame #n−1and the line in frame #n+1.

In frame #n, the foreground components corresponding to the objectcontained in the sixth through seventeenth pixels from the left arecontained in the second through thirteenth pixels from the left in frame#n−1 and are also contained in the tenth through twenty-first pixel fromthe left in frame #n+1.

In frame #n−1, the pixels belonging to the covered background area arethe eleventh through thirteenth pixels from the left, and the pixelsbelonging to the uncovered background area are the second through fourthpixels from the left. In frame #n, the pixels belonging to the coveredbackground area are the fifteenth through seventeenth pixels from theleft, and the pixels belonging to the uncovered background area are thesixth through eighth pixels from the left. In frame #n+1, the pixelsbelonging to the covered background area are the nineteenth throughtwenty-first pixels from the left, and the pixels belonging to theuncovered background area are the tenth through twelfth pixels from theleft.

In frame #n−1, the pixels belonging to the background area are the firstpixel from the left, and the fourteenth through twenty-first pixels fromthe left. In frame #n, the pixels belonging to the background area arethe first through fifth pixels from the left, and the eighteenth throughtwenty-first pixels from the left. In frame #n+1, the pixels belongingto the background area are the first through ninth pixels from the left.

An example of the background image corresponding to the example shown inFIG. 37 generated by the background image generator 301 is shown in FIG.38. The background image consists of the pixels corresponding to thebackground object, and does not contain image components correspondingto the foreground object.

The binary-object-image extracting portion 302 generates a binary objectimage based on the correlation between the background image and theinput image, and supplies the generated binary object image to a timechange detector 303.

FIG. 39 is a block diagram illustrating the configuration of thebinary-object-image extracting portion 302. A correlation-valuecalculator 321 calculates the correlation between the background imagesupplied from the background image generator 301 and the input image soas to generate a correlation value, and supplies the generatedcorrelation value to a threshold-value processor 322.

The correlation-value calculator 321 applies equation (4) to, forexample, a 3×3-background image block having X₄ at the center, as shownin FIG. 40A, and to, for example, a 3×3-background image block having Y₄at the center which corresponds to the background image block, as shownin FIG. 40B, thereby calculating a correlation value corresponding toY₄.

$\begin{matrix}{{{Correlation}\mspace{14mu}{value}} = \frac{\sum\limits_{i = 0}^{8}{\left( {{Xi} - \overset{\_}{X}} \right){\sum\limits_{i = 0}^{8}\left( {{Yi} - \overset{\_}{Y}} \right)}}}{\sqrt{\sum\limits_{i = 0}^{8}{\left( {{Xi} - \overset{\_}{X}} \right)^{2} \cdot {\sum\limits_{i = 0}^{8}\left( {{Yi} - \overset{\_}{Y}} \right)^{2}}}}}} & (4) \\{\overset{\_}{X} = \frac{\sum\limits_{i = 0}^{8}{Xi}}{9}} & (5) \\{\overset{\_}{Y} = \frac{\sum\limits_{i = 0}^{8}{Yi}}{9}} & (6)\end{matrix}$

The correlation-value calculator 321 supplies the correlation valuecalculated for each pixel as discussed above to the threshold-valueprocessor 322.

Alternatively, the correlation-value calculator 321 may apply equation(7) to, for example, a 3×3-background image block having X₄ at thecenter, as shown in FIG. 41A, and to, for example, a 3×3-backgroundimage block having Y₄ at the center which corresponds to the backgroundimage block, as shown in FIG. 41B, thereby calculating the sum ofabsolute values of differences corresponding to Y₄.

$\begin{matrix}{{{Sum}\mspace{14mu}{of}\mspace{14mu}{absolute}\mspace{14mu}{values}\mspace{14mu}{of}\mspace{14mu}{differences}} = {\sum\limits_{i = 0}^{8}{\left( {{Xi} - {Yi}} \right)}}} & (7)\end{matrix}$

The correlation-value calculator 321 supplies the sum of the absolutevalues of the differences calculated as described above to thethreshold-value processor 322 as the correlation value.

The threshold-value processor 322 compares the pixel value of thecorrelation image with a threshold value th0. If the correlation valueis smaller than or equal to the threshold value th0, 1 is set in thepixel value of the binary object image. If the correlation value isgreater than the threshold value th0, 0 is set in the pixel value of thebinary object image. The threshold-value processor 322 then outputs thebinary object image whose pixel value is set to 0 or 1. Thethreshold-value processor 322 may store the threshold value th0 thereinin advance, or may use the threshold value th0 input from an externalsource.

FIG. 42 illustrates the binary object image corresponding to the modelof the input image shown in FIG. 37. In the binary object image, 0 isset in the pixel values of the pixels each having a higher correlationwith the background image.

FIG. 43 is a block diagram illustrating the configuration of the timechange detector 303. When determining the area of a pixel in frame #n, aframe memory 341 stores a binary object image of frame #n−1 frame #n,and frame #n+1 supplied from the binary-object-image extracting portion302.

An area determining portion 342 determines the area of each pixel offrame #n based on the binary object image of frame #n−1, frame #n, andframe #n+1 so as to generate area information, and outputs the generatedarea information.

FIG. 44 illustrates the determinations made by the area determiningportion 342. When the designated pixel of the binary object image inframe #n is 0, the area determining portion 342 determines that thedesignated pixel in frame #n belongs to the background area.

When the designated pixel of the binary object image in frame #n is 1,and when the corresponding pixel of the binary object image in frame#n−1 is 1, and when the corresponding pixel of the binary object imagein frame #n+1 is 1, the area determining portion 342 determines that thedesignated pixel in frame #n belongs to the foreground area.

When the designated pixel of the binary object image in frame #n is 1,and when the corresponding pixel of the binary object image in frame#n−1 is 0, the area determining portion 342 determines that thedesignated pixel in frame #n belongs to a covered background area.

When the designated pixel of the binary object image in frame #n is 1,and when the corresponding pixel of the binary object image in frame#n+1 is 0, the area determining portion 342 determines that thedesignated pixel in frame #n belongs to an uncovered background area.

FIG. 45 illustrates an example of the determinations made by the timechange detector 303 on the binary object image corresponding to themodel of the input image shown in FIG. 37. The time change detector 303determines that the first through fifth pixels from the left in frame.#n belong to the background area since the corresponding pixels of thebinary object image in frame #n are 0.

The time change detector 303 determines that the sixth through ninthpixels from the left belong to the uncovered background area since thepixels of the binary object image in frame #n are 1, and thecorresponding pixels in frame #n+1 are 0.

The time change detector 303 determines that the tenth throughthirteenth pixels from the left belong to the foreground area since thepixels of the binary object image in frame #n are 1, the correspondingpixels in frame #n−1 are 1, and the corresponding pixels in frame #n+1are 1.

The time change detector 303 determines that the fourteenth throughseventeenth pixels from the left belong to the covered background areasince the pixels of the binary object image in frame #n are 1, and thecorresponding pixels in frame #n−1 are 0.

The time change detector 303 determines that the eighteenth throughtwenty-first pixels from the left belong to the background area sincethe corresponding pixels of the binary object image in frame #n are 0.

The area specifying processing performed by the area specifying unit 103is described below with reference to the flowchart of FIG. 46. In stepS301, the background image generator 301 of the area specifying unit 103extracts, for example, an image object corresponding to a backgroundobject contained in an input image based on the input image so as togenerate a background image, and supplies the generated background imageto the binary-object-image extracting portion 302.

In step S302, the binary-object-image extracting portion 302 calculatesa correlation value between the input image and the background imagesupplied from the background image generator 301 according to, forexample, calculation discussed with reference to FIGS. 40A and 40B. Instep S303, the binary-object-image extracting portion 302 computes abinary object image from the correlation value and the threshold valueth0 by, for example, comparing the correlation value with the thresholdvalue th0.

In step S304, the time change detector 303 executes the area determiningprocessing, and the processing is completed.

Details of the area determining processing in step S304 are describedbelow with reference to the flowchart of FIG. 47. In step S321, the areadetermining portion 342 of the time change detector 303 determineswhether the designated pixel in frame #n stored in the frame memory 341is 0. If it is determined that the designated pixel in frame #n is 0,the process proceeds to step S322. In step S322, it is determined thatthe designated pixel in frame #n belongs to the background area, and theprocessing is completed.

If it is determined in step S321 that the designated pixel in frame #nis 1, the process proceeds to step S323. In step S323, the areadetermining portion 342 of the time change detector 303 determineswhether the designated pixel in frame #n stored in the frame memory 341is 1, and whether the corresponding pixel in frame #n−1 is 0. If it isdetermined that the designated pixel in frame #n is 1 and thecorresponding pixel in frame #n−1 is 0, the process proceeds to stepS324. In step S324, it is determined that the designated pixel in frame#n belongs to the covered background area, and the processing iscompleted.

If it is determined in step S323 that the designated pixel in frame #nis 0, or that the corresponding pixel in frame #n−1 is 1, the processproceeds to step S325. In step S325, the area determining portion 342 ofthe time change detector 303 determines whether the designated pixel inframe #n stored in the frame memory 341 is 1, and whether thecorresponding pixel in frame #n+1 is 0. If it is determined that thedesignated pixel in frame #n is 1 and the corresponding pixel in frame#n+1 is 0, the process proceeds to step S326. In step S326, it isdetermined that the designated pixel in frame #n belongs to theuncovered background area, and the processing is completed.

If it is determined in step S325 that the designated pixel in frame #nis 0, or that the corresponding pixel in frame #n+1 is 1, the processproceeds to step S327. In step S327, the area determining portion 342 ofthe time change detector 303 determines that the designated pixel inframe #n belongs to the foreground area, and the processing iscompleted.

As discussed above, the area specifying unit 103 is able to specify,based on the correlation value between the input image and thecorresponding background image, to which of the foreground area, thebackground area, the covered background area, or the uncoveredbackground area each pixel of the input image belongs, and generatesarea information corresponding to the specified result.

FIG. 48 is a block diagram illustrating another configuration of thearea specifying unit 103. The area specifying unit 103 shown in FIG. 48uses a motion vector and positional information thereof supplied fromthe motion detector 102. The same elements as those shown in FIG. 36 aredesignated with like reference numerals, and an explanation thereof isthus omitted.

A robust-processing portion 361 generates a robust binary object imagebased on binary object images of N frames supplied from thebinary-object-image extracting portion 302, and outputs the robustbinary object image to the time change detector 303.

FIG. 49 is a block diagram illustrating the configuration of therobust-processing portion 361. A motion compensator 381 compensates forthe motion of the binary object images of N frames based on the motionvector and the positional information thereof supplied from the motiondetector 102, and outputs a motion-compensated binary object image to aswitch 382.

The motion compensation performed by the motion compensator 381 isdiscussed below with reference to examples shown in FIGS. 50 and 51. Itis now assumed, for example, that the area in frame #n is to beprocessed. When binary object images of frame #n−1, frame #n, and frame#n+1 shown in FIG. 50 are input, the motion compensator 381 compensatesfor the motion of the binary object image of frame #n−1 and the binaryobject image of frame #n+1, as indicated by the example shown in FIG.51, based on the motion vector supplied from the motion detector 102,and supplies the motion-compensated binary object images to the switch382.

The switch 382 outputs the motion-compensated binary object image of thefirst frame to a frame memory 383-1, and outputs the motion-compensatedbinary object image of the second frame to a frame memory 383-2.Similarly, the switch 382 outputs the motion-compensated binary objectimages of the third through (N−1)-th frame to frame memories 383-3through 383-(N−1), and outputs the motion-compensated binary objectimage of the N-th frame to a frame memory 383-N.

The frame memory 383-1 stores the motion-compensated binary object imageof the first frame, and outputs the stored binary object image to aweighting portion 384-1. The frame memory 383-2 stores themotion-compensated binary object image of the second frame, and outputsthe stored binary object image to a weighting portion 384-2.

Similarly, the frame memories 383-3 through 383-(N−1) stores themotion-compensated binary object images of the third through (N−1)-thframes, and outputs the stored binary object images to weightingportions 384-3 through 384-(N−1). The frame memory 383-N stores themotion-compensated binary object image of the N-th frame, and outputsthe stored binary object image to a weighting portion 384-N.

The weighting portion 384-1 multiplies the pixel value of themotion-compensated binary object image of the first frame supplied fromthe frame memory 383-1 by a predetermined weight w1, and supplies aweighted binary object image to an accumulator 385. The weightingportion 384-2 multiplies the pixel value of the motion-compensatedbinary object image of the second frame supplied from the frame memory383-2 by a predetermined weight w2, and supplies the weighted binaryobject image to the accumulator 385.

Likewise, the weighting portions 384-3 through 384-(N−1) multiply thepixel values of the motion-compensated binary object images of the thirdthrough (N−1)-th frames supplied from the frame memories 383-3 through383-(N−1) by predetermined weights w3 through w(N−1), and supplies theweighted binary object images to the accumulator 385. The weightingportion 384-N multiplies the pixel value of the motion-compensatedbinary object image of the N-th frame supplied from the frame memory383-N by a predetermined weight wN, and supplies the weighted binaryobject image to the accumulator 385.

The accumulator 385 accumulates the pixel values of themotion-compensated binary object images multiplied by the weights w1through wN of the first through N-th frames, and compares theaccumulated pixel value with the predetermined threshold value th0,thereby generating the binary object image.

As discussed above, the robust-processing portion 361 generates a robustbinary object image from N binary object images, and supplies it to thetime change detector 303. Accordingly, the area specifying unit 103configured as shown in FIG. 48 is able to specify the area moreprecisely than that shown in FIG. 36 even if noise is contained in theinput image.

The area specifying processing performed by the area specifying unit 103configured as shown in FIG. 48 is described below with reference to theflowchart of FIG. 52. The processings of step S341 through step S343 aresimilar to those of step S301 through step S303 discussed with referenceto the flowchart of FIG. 46, and an explanation thereof is thus omitted.

In step S344, the robust-processing portion 361 performs the robustprocessing.

In step S345, the time change detector 303 performs the area determiningprocessing, and the processing is completed. Details of the processingof step S345 are similar to the processing discussed with reference tothe flowchart of FIG. 47, and an explanation thereof is thus omitted.

Details of the robust processing corresponding to the processing of stepS344 in FIG. 52 are given below with reference to the flowchart of FIG.53. In step S361, the motion compensator 381 performs the motioncompensation of an input binary object image based on the motion vectorand the positional information thereof supplied from the motion detector102. In step S362, one of the frame memories 383-1 through 383-N storesthe corresponding motion-compensated binary object image supplied viathe switch 382.

In step S363, the robust-processing portion 361 determines whether Nbinary object images are stored. If it is determined that N binaryobject images are not stored, the process returns to step S361, and theprocessing for compensating for the motion of the binary object imageand the processing for storing the binary object image are repeated.

If it is determined in step S363 that N binary object images are stored,the process proceeds to step S364 in which weighting is performed. Instep S364, the weighting portions 384-1 through 384-N multiply thecorresponding N binary object images by the weights w1 through wN.

In step S365, the accumulator 385 accumulates the N weighted binaryobject images.

In step S366, the accumulator 385 generates a binary object image fromthe accumulated images by, for example, comparing the accumulated valuewith a predetermined threshold value th1, and the processing iscompleted.

As discussed above, the area specifying unit 103 configured as shown inFIG. 48 is able to generate area information based on the robust binaryobject image.

As is seen from the foregoing description, the area specifying unit 103is able to generate area information indicating to which of the movingarea, the stationary area, the uncovered background area, or the coveredbackground area each pixel contained in a frame belongs.

FIG. 54 is a block diagram illustrating the configuration of themixture-ratio calculator 104. An estimated-mixture-ratio processor 401calculates an estimated mixture ratio for each pixel by calculating amodel of a covered background area based on the input image, andsupplies the calculated estimated mixture ratio to a mixture-ratiodetermining portion 403.

An estimated-mixture-ratio processor 402 calculates an estimated mixtureratio for each pixel by calculating a model of an uncovered backgroundarea based on the input image, and supplies the calculated estimatedmixture ratio to the mixture-ratio determining portion 403.

Since it can be assumed that the object corresponding to the foregroundis moving with constant velocity within the shutter time, the mixtureratio α of the pixels belonging to a mixed area exhibits the followingcharacteristics. That is, the mixture ratio α linearly changes accordingto the positional change in the pixels. If the positional change in thepixels is one-dimensional, a change in the mixture ratio α can berepresented linearly. If the positional change in the pixels istwo-dimensional, a change in the mixture ratio α can be represented on aplane.

Since the period of one frame is short, it can be assumed that theobject corresponding to the foreground is a rigid body moving withconstant velocity.

The gradient of the mixture ratio α is inversely proportional to theamount of movement v within the shutter time of the foreground.

An example of the ideal mixture ratio α is shown in FIG. 55. Thegradient 1 of the ideal mixture ratio α in the mixed area can berepresented by the reciprocal of the amount of movement v.

As shown in FIG. 55, the ideal mixture ratio α has the value of 1 in thebackground area, the value of 0 in the foreground area, and the value ofgreater than 0 and smaller than 1 in the mixed area.

In the example shown in FIG. 56, the pixel value C06 of the seventhpixel from the left in frame #n can be indicated by equation (8) byusing the pixel value P06 of the seventh pixel from the left in frame#n−1.

$\begin{matrix}\begin{matrix}{{C06} = {{{B06}/v} + {{B06}/v} + {{F01}/v} + {{F02}/v}}} \\{= {{{P06}/v} + {{P06}/v} + {{F01}/v} + {{F02}/v}}} \\{= {{{2/v} \cdot {P06}} + {\sum\limits_{i = 1}^{2}{{Fi}/v}}}}\end{matrix} & (8)\end{matrix}$

In equation (8), the pixel value C06 is indicated by a pixel value M ofthe pixel in the mixed area, while the pixel value P06 is indicated by apixel value B of the pixel in the background area. That is, the pixelvalue M of the pixel in the mixed area and the pixel value B of thepixel in the background area can be represented by equations (9) and(10), respectively.M=C06  (9)B=P06  (10)

In equation (8), 2/v corresponds to the mixture ratio α. Since theamount of movement v is 4, the mixture ratio α of the seventh pixel fromthe left in frame #n is 0.5.

As discussed above, the pixel value C in the designated frame #n isconsidered as the pixel value in the mixed area, while the pixel value Pof frame #n−1 prior to frame #n is considered as the pixel value in thebackground area. Accordingly, equation (3) indicating the mixture ratioα can be represented by equation (11):C=α·P+f  (11)

where f in equation (11) indicates the sum of the foreground componentsΣ_(i)Fi/v contained in the designated pixel. The variables contained inequation (11) are two factors, i.e., the mixture ratio α and the sum fof the foreground components.

Similarly, a model obtained by expanding in the time direction the pixelvalues in which the amount of movement is 4 and the number of virtualdivided portions is 4 in an uncovered background area is shown in FIG.57.

As in the representation of the covered background area, in theuncovered background area, the pixel value C of the designated frame #nis considered as the pixel value in the mixed area, while the pixelvalue N of frame #n+1 subsequent to frame #n is considered as thebackground area. Accordingly, equation (3) indicating the mixture ratioα can be represented by equation (12).C=α·N+f  (12)

The embodiment has been described, assuming that the background objectis stationary. However, equations (8) through (12) can be applied to thecase in which the background object is moving by using the pixel valueof a pixel located corresponding to the amount of movement v of thebackground. It is now assumed, for example, in FIG. 56 that the amountof movement v of the object corresponding to the background is 2, andthe number of virtual divided portions is 2. In this case, when theobject corresponding to the background is moving to the right in FIG.49, the pixel value B of the pixel in the background area in equation(10) is represented by a pixel value P04.

Since equations (11) and (12) each contain two variables, the mixtureratio α cannot be determined without modifying the equations. Since thespatial correlation in an image is generally strong, neighboring pixelsare of substantially the same pixel value.

Since the spatial correlation of foreground components is strong, theequation is transformed so that the sum f of the foreground componentscan be obtained from the previous or subsequent frame and computes themixture ratio α.

The pixel value Mc of the seventh pixel from the left in frame #n ofFIG. 58 can be expressed by equation (13):

$\begin{matrix}{{M\; c} = {{\frac{2}{v} \cdot {B06}} + {\sum\limits_{i = 11}^{12}{{Fi}/v}}}} & (13)\end{matrix}$

where 2/v of the first term of the right side of equation (13)corresponds to the mixture ratio α. The second term of the right side ofequation (13) is expressed by equation (14) using a pixel value in thesubsequent frame #n+1:

$\begin{matrix}{{\sum\limits_{i = 11}^{12}{{Fi}/v}} = {\beta \cdot {\sum\limits_{i = 7}^{10}{{Fi}/v}}}} & (14)\end{matrix}$

By utilizing the spatial correlation of the foreground components,equation (15) holds true:F=F05=F06=F07=F08=F09=F10=F11=F12  (15)

Equation (14) can be replaced by equation (16) by utilizing equation(15):

$\begin{matrix}\begin{matrix}{{\sum\limits_{i = 11}^{12}{{Fi}/v}} = {\frac{2}{v} \cdot F}} \\{= {\beta \cdot \frac{4}{v} \cdot F}}\end{matrix} & (16)\end{matrix}$

As a result, β can be expressed by equation (17):β= 2/4  (17)

In general, as shown by equation (15), given that the foregroundcomponents related to the mixed area are equal, equation (18) holds truewith respect to all pixels in the mixed area on the basis of theinternal ratio relationship:β=1−α  (18)

If equation (18) holds true, equation (11) can be expanded as shown byequation (19):

$\begin{matrix}\begin{matrix}{C = {{\alpha \cdot P} + f}} \\{= {{\alpha \cdot P} + {\left( {1 - \alpha} \right) \cdot {\sum\limits_{i = \gamma}^{\gamma + V - 1}{{Fi}/v}}}}} \\{= {{\alpha \cdot P} + {\left( {1 - \alpha} \right) \cdot N}}}\end{matrix} & (19)\end{matrix}$

Similarly, if equation (18) holds true, equation (12) can be expanded asshown by equation (20):

$\begin{matrix}\begin{matrix}{C = {{\alpha \cdot N} + f}} \\{= {{\alpha \cdot N} + {\left( {1 - \alpha} \right) \cdot {\sum\limits_{i = \gamma}^{\gamma + V - 1}{{Fi}/v}}}}} \\{= {{\alpha \cdot N} + {\left( {1 - \alpha} \right) \cdot P}}}\end{matrix} & (20)\end{matrix}$

In equations (19) and (20), C, N, and P are known values, and the mixedratio α is the only variable included in equations (19) and (20). Therelationship among C, N, and P in equations (19) and (20) is shown inFIG. 59. C is the pixel value of the designated pixel in frame #n, forwhich the mixture ratio α is to be computed. N is the pixel value of thepixel in frame #n+1, whose position in the spatial direction correspondsto that of the designated pixel. P is the pixel value of the pixel inframe #n−1 whose position in the spatial direction corresponds to thatof the designated pixel.

Since one variable is included in each of equations (19) and (20), themixture ratio α can be computed by utilizing the pixel values of thepixels in the three frames. The condition for computing the correctmixture ratio α by solving equations (19) and (20) is that theforeground components related to the mixed area are equal. In otherwords, in a foreground image object of an image captured when aforeground object is stationary, consecutive pixels (the number ofpixels is twice the amount of movement v) which correspond to adirection in which the foreground object is moving and which are locatedat the boundary of the image object have a constant pixel value.

As discussed above, the mixture ratio α for a pixel belonging to thecovered background area is computed by equation (21), and the mixtureratio α for a pixel belonging to the uncovered background area iscomputed by equation (22):α=(C−N)/(P−N)  (21)α=(C−P)/(N−P)  (22)

FIG. 60 is a block diagram illustrating the configuration of theestimated-mixture-ratio processor 401. A frame memory 421 stores aninput image in units of frames and supplies one frame subsequent to aframe input as an input image to a frame memory 422 and a mixture-ratiocalculator 423.

The frame memory 422 stores the input image in units of frames andsupplies one frame subsequent to the frame supplied from the framememory 421 to the mixture-ratio calculator 423.

When frame #n+1 is input as the input image to the mixture-ratiocalculator 423, the frame memory 421 supplies frame #n to themixture-ratio calculator 423, and the frame memory 422 supplies frame#n−1 to the mixture-ratio calculator 423.

The mixture-ratio calculator 423 calculates equation (21) to compute anestimated mixture ratio for the designated pixel on the basis of thepixel value C of the designated pixel in frame #n, the pixel value N ofthe pixel in frame #n+1, whose spatial position corresponds to that ofthe designated pixel, and the pixel value P of the pixel in frame #n−1,whose spatial position corresponds to that of the designated pixel, andoutputs the computed estimated mixture ratio. For example, when thebackground is stationary, the mixture-ratio calculator 423 computes anestimated mixture ratio for the designated pixel on the basis of thepixel value C of the designated pixel in frame #n, the pixel value N ofthe pixel in frame #n+1, whose position in the frame is the same as thatof the designated pixel, and the pixel value P of the pixel in frame#n−1, whose position in the frame is the same as that of the designatedpixel, and outputs the computed estimated mixture ratio.

In this manner, the estimated-mixture-ratio processor 401 is able tocalculate the estimated mixture ratio based on the input image, andsupplies it to the mixture-ratio determining portion 403.

Since the estimated-mixture-ratio processor 402 is similar to theestimated-mixture-ratio processor 401 except for the fact that theestimated-mixture-ratio processor 401 calculates equation (21) tocompute the estimated mixture ratio for the designated pixel whereas theestimated-mixture-ratio processor 402 calculates equation (22) tocompute the estimated mixture ratio for the designated pixel, adescription thereof is omitted.

FIG. 61 illustrates an example of an estimated mixture ratio calculatedby the estimated-mixture-ratio processor 401. The estimated mixtureratio shown in FIG. 61 indicates the result of a case, with respect toone line, in which the amount of movement v in the foregroundcorresponding to an object moving at a constant speed is 11.

FIG. 55 shows that the estimated mixture ratio changes substantiallylinearly in the mixed area.

Referring back to FIG. 54, the mixture-ratio determining portion 403sets the mixture ratio α based on the area information supplied from thearea specifying unit 103 and indicating to which of the foreground area,the background area, the covered background area, or the uncoveredbackground area the pixel for which the mixture ratio α is to becalculated belongs. The mixture-ratio determining portion 403 sets themixture ratio α to 0 when the corresponding pixel belongs to theforeground area, and sets the mixture ratio α to 1 when thecorresponding pixel belongs to the background area. When thecorresponding pixel belongs to the covered background area, themixture-ratio determining portion 403 sets the estimated mixture ratiosupplied from the estimated-mixture-ratio processor 401 as the mixtureratio α. When the corresponding pixel belongs to the uncoveredbackground area, the mixture-ratio determining portion 403 sets theestimated mixture ratio supplied from the estimated-mixture-ratioprocessor 402 as the mixture ratio α. The mixture-ratio determiningportion 403 outputs the mixture ratio α which has been set based on thearea information.

FIG. 62 is a block diagram illustrating another configuration of themixture-ratio calculator 104. A selector 441 supplies a pixel belongingto the covered background area and the corresponding pixels in theprevious frame and the subsequent frame to an estimated-mixture-ratioprocessor 442 based on the area information supplied from the areaspecifying unit 103. The selector 441 supplies a pixel belonging to theuncovered background area and the corresponding pixels in the previousframe and the subsequent frame to an estimated-mixture-ratio processor443 based on the area information supplied from the area specifying unit103.

The estimated-mixture-ratio processor 442 calculates equation (21) basedon the pixel values input from the selector 441 to compute an estimatedmixture ratio for the designated pixel, which belongs to the coveredbackground area, and supplies the computed estimated mixture ratio to aselector 444.

The estimated-mixture-ratio processor 443 calculates equation (22) basedon the pixel values input from the selector 441 to compute an estimatedmixture ratio for the designated pixel, which belongs to the uncoveredbackground area, and supplies the calculated estimated mixture ratio tothe selector 444.

Based on the area information supplied from the area specifying unit103, the selector 444 sets the mixture ratio α to 0 when the designatedpixel belongs to the foreground area, and sets the mixture ratio α to 1when the designated pixel belongs to the background area. When thedesignated pixel belongs to the covered background area, the selector444 selects the estimated mixture ratio supplied from theestimated-mixture-ratio processor 442 and sets it as the mixture ratioα. When the designated pixel belongs to the uncovered background area,the selector 444 selects the estimated mixture ratio supplied from theestimated-mixture-ratio processor 443 and sets it as the mixture ratioα. The selector 444 then outputs the mixture ratio α which has beenselected and set based on the area information.

As discussed above, the mixture-ratio calculator 104 configured as shownin FIG. 62 is able to calculate the mixture ratio α for each pixelcontained in the image, and outputs the calculated mixture ratio α.

The calculation processing for the mixture ratio α performed by themixture-ratio calculator 104 configured as shown in FIG. 54 is discussedbelow with reference to the flowchart of FIG. 63. In step S401, themixture-ratio calculator 104 obtains area information supplied from thearea specifying unit 103. In step S402, the estimated-mixture-ratioprocessor 401 executes the processing for estimating the mixture ratioby using a model corresponding to a covered background area, andsupplies the estimated mixture ratio to the mixture-ratio determiningportion 403. Details of the processing for estimating the mixture ratioare discussed below with reference to the flowchart of FIG. 64.

In step S403, the estimated-mixture-ratio processor 402 executes theprocessing for estimating the mixture ratio by using a modelcorresponding to an uncovered background area, and supplies theestimated mixture ratio to the mixture-ratio determining portion 403.

In step S404, the mixture-ratio calculator 104 determines whether themixture ratios have been estimated for the whole frame. If it isdetermined that the mixture ratios have not yet been estimated for thewhole frame, the process returns to step S402, and the processing forestimating the mixture ratio for the subsequent pixel is executed.

If it is determined in step S404 that the mixture ratios have beenestimated for the whole frame, the process proceeds to step S405. Instep S405, the mixture-ratio determining portion 403 sets the mixtureratio based on the area information supplied from the area specifyingunit 103 and indicating to which of the foreground area, the backgroundarea, the covered background area, or the uncovered background area thepixel for which the mixture ratio α is to be calculated belongs. Themixture-ratio determining portion 403 sets the mixture ratio α to 0 whenthe corresponding pixel belongs to the foreground area, and sets themixture ratio α to 1 when the corresponding pixel belongs to thebackground area. When the corresponding pixel belongs to the coveredbackground area, the mixture-ratio determining portion 403 sets theestimated mixture ratio supplied from the estimated-mixture-ratioprocessor 401 as the mixture ratio α. When the corresponding pixelbelongs to the uncovered background area, the mixture-ratio determiningportion 403 sets the estimated mixture ratio supplied from theestimated-mixture-ratio processor 402 as the mixture ratio α. Theprocessing is then completed.

As discussed above, the mixture-ratio calculator 104 is able tocalculate the mixture ratio α, which indicates a feature quantitycorresponding to each pixel, based on the area information supplied fromthe area specifying unit 103, and the input image.

The processing for calculating the mixture ratio α performed by themixture-ratio calculator 104 configured as shown in FIG. 62 is similarto that discussed with reference to the flowchart of FIG. 63, and anexplanation thereof is thus omitted.

A description is now given, with reference to the flowchart of FIG. 64,of the mixture-ratio estimating processing by using a model of thecovered background area in step S402 of FIG. 63.

In step S421, the mixture-ratio calculator 423 obtains the pixel value Cof the designated pixel in frame #n from the frame memory 421.

In step S422, the mixture-ratio calculator 423 obtains the pixel value Pof the pixel in frame #n−1, which corresponds to the designated pixel,from the frame memory 422.

In step S423, the mixture-ratio calculator 423 obtains the pixel value Nof the pixel in frame #n+1, which corresponds to the designated pixelincluded in the input image.

In step S424, the mixture-ratio calculator 423 calculates an estimatedmixture ratio based on the pixel value C of the designated pixel inframe #n, the pixel value P of the pixel in frame #n−1 and the pixelvalue N of the pixel in frame #n+1.

In step S425, the mixture-ratio calculator 423 determines whether theprocessing for calculating estimated mixture ratios in the entire frameis completed. If it is determined that the processing for calculatingestimated mixture ratios in the entire frame is not completed, theprocess returns to step S421 and repeats the processing for calculatingan estimated mixture ratio for the subsequent pixel.

If it is determined in step S425 that the processing for calculatingestimated mixture ratios in the entire frame is completed, theprocessing is terminated.

As discussed above, the estimated-mixture-ratio processor 401 is able tocalculate the estimated mixture ratio based on the input image.

The mixture-ratio estimating processing by using a model correspondingto the uncovered background area in step S403 of FIG. 63 is similar tothe processing indicated by the flowchart of FIG. 64 by using theequations corresponding to a model of the uncovered background area, andan explanation thereof is thus omitted.

Since the estimated-mixture-ratio processor 442 and theestimated-mixture-ratio processor 443 shown in FIG. 62 perform theprocessing similar to that shown by the flowchart of FIG. 64 tocalculate estimated mixture ratios, descriptions thereof are omitted.

The embodiment has been described, assuming that the objectcorresponding to the background is stationary. However, theabove-described processing for calculating the mixture-ratio α can beapplied even if the image corresponding to the background area containsmotion. For example, if the image corresponding to the background areais uniformly moving, the estimated-mixture-ratio processor 401 shiftsthe overall image in accordance with the background motion, and performsprocessing in a manner similar to the case in which the objectcorresponding to the background is stationary. If the imagecorresponding to the background area contains locally differentbackground motions, the estimated-mixture-ratio processor 401 selectsthe pixels corresponding to the background motions as the pixelsbelonging to the mixed area, and executes the above-describedprocessing.

The mixture-ratio calculator 104 may execute the mixture-ratioestimating processing on all the pixels only by using a modelcorresponding to the covered background area, and outputs the calculatedestimated mixture ratio as the mixture ratio α. In this case, themixture ratio α indicates the ratio of the background components for thepixels belonging to the covered background area, and indicates the ratioof the foreground components for the pixels belonging to the uncoveredbackground area. Concerning the pixels belonging to the uncoveredbackground area, the absolute value of the difference between thecalculated mixture ratio α and 1 is determined, and the calculatedabsolute value is set as the mixture ratio α. Then, the separatingportion 91 is able to determine the mixture ratio α indicating the ratioof the background components for the pixels belonging to the uncoveredbackground area.

Similarly, the mixture-ratio processor 104 may execute the mixture-ratioestimating processing on all the pixels only by using a modelcorresponding to the uncovered background area, and outputs thecalculated estimated mixture ratio as the mixture ratio α.

The mixture-ratio calculator 104 for calculating the mixture ratio αusing the characteristic that the mixture ratio α changes linearly willnow be described.

As described above, since equations (11) and (12) each contain twovariables, the mixture ratio α cannot be determined without modifyingthe equations.

The mixture ratio α linearly changes in accordance with a change in theposition of the pixels because the object corresponding to theforeground is moving with constant velocity. By utilizing thischaracteristic, an equation in which the mixture ratio α and the sum fof the foreground components are approximated in the spatial directioncan hold true. By utilizing a plurality of sets of the pixel values ofthe pixels belonging to the mixed area and the pixel values of thepixels belonging to the background area, the equation in which themixture ratio α and the sum f of the foreground components areapproximated is solved.

When a change in the mixture ratio α is approximated as a straight line,the mixture ratio α can be expressed by equation (23).α=il+p  (23)

In equation (23), i indicates the spatial index when the position of thedesignated pixel is set to 0, 1 designates the gradient of the straightline of the mixture ratio α, and p designates the intercept of thestraight line of the mixture ratio α and also indicates the mixtureratio α of the designated pixel. In equation (23), the index i is known,and the gradient 1 and the intercept p are unknown.

The relationship among the index i, the gradient 1, and the intercept pis shown in FIG. 65. In FIG. 65, the white dot indicates the designatedpixel, and the black dots indicate neighboring pixels.

By approximating the mixture ratio α as equation (23), a plurality ofdifferent mixture ratios a for a plurality of pixels can be expressed bytwo variables. In the example shown in FIG. 65, the five mixture ratiosfor five pixels are expressed by the two variables, i.e., the gradient 1and the intercept p.

When the mixture ratio α is approximated in the plane shown in FIG. 66,equation (23) is expanded into the plane by considering the movement vcorresponding to the two directions, i.e., the horizontal direction andthe vertical direction of the image, and the mixture ratio α can beexpressed by equation (24). In FIG. 66, the white dot indicates thedesignated pixel.α=jm+kq+p  (24)

In equation (24), j is the index in the horizontal direction, and k isthe index in the vertical direction when the position of the designatedpixel is 0. In equation (24), m designates the horizontal gradient ofthe mixture ratio α in the plane, and q indicates the vertical gradientof the mixture ratio α in the plane. In equation (24), p indicates theintercept of the mixture ratio α in the plane.

For example, in frame #n shown in FIG. 56, equations (25) through (27)can hold true for C05 through C07, respectively.C05=α05·B05/v+f05  (25)C06=α06·B06/v+f06  (26)C07=α07·B07/v+f07  (27)

Assuming that the foreground components positioned in close proximitywith each other are equal to each other, i.e., that F01 through F03 areequal, equation (28) holds true by replacing F01 through F03 by fc.f(x)=(1−α(x))·Fc  (28)

In equation (28), x indicates the position in the spatial direction.

When α(x) is replaced by equation (24), equation (28) can be expressedby equation (29).

$\begin{matrix}\begin{matrix}{{f(x)} = {\left( {1 - \left( {{jm} + {kq} + p} \right)} \right) \cdot {Fc}}} \\{= {{j \cdot \left( {{- m} \cdot {Fc}} \right)} + {k \cdot \left( {{- q} \cdot {Fc}} \right)} + \left( {\left( {1 - p} \right) \cdot {Fc}} \right)}} \\{= {{js} + {kt} + u}}\end{matrix} & (29)\end{matrix}$

In equation (29), (−m·Fc), (−q·Fc), and (1−p)·Fc are replaced, asexpressed by equations (30) through (32), respectively.s=−m·Fc  (30)t=−q·Fc  (31)u=(1−p)·Fc  (32)

In equation (29), j is the index in the horizontal direction, and k isthe index in the vertical direction when the position of the designatedpixel is 0.

As discussed above, since it can be assumed that the objectcorresponding to the foreground is moving with constant velocity withinthe shutter period, and that the foreground components positioned inclose proximity with each other are uniform, the sum of the foregroundcomponents can be approximated by equation (29).

When the mixture ratio α is approximated by a straight line, the sum ofthe foreground components can be expressed by equation (33).f(x)=is+u  (33)

By replacing the mixture ratio α and the sum of the foregroundcomponents in equation (13) by using equations (24) and (29), the pixelvalue M can be expressed by equation (34).

$\begin{matrix}\begin{matrix}{M = {{\left( {{jm} + {kq} + p} \right) \cdot B} + {js} + {kt} + u}} \\{= {{{jB} \cdot m} + {{kB} \cdot q} + {B \cdot p} + {j \cdot s} + {k \cdot t} + u}}\end{matrix} & (34)\end{matrix}$

In equation (34), unknown variables are six factors, such as thehorizontal gradient m of the mixture ratio α in the plane, the verticalgradient q of the mixture ratio α in the plane, and the intercepts ofthe mixture ratio α in the plane, p, s, t, and u.

According to the pixels in close proximity with the designated pixel,the pixel value M or the pixel value B is set in the normal equationshown by equation (34). Then, a plurality of normal equations in whichthe pixel value M or the pixel value B is set are solved by the methodof least squares, thereby calculating the mixture ratio α.

For example, the horizontal index j of the designated pixel is set to 0,and the vertical index k is set to 0. Then, the pixel value M or thepixel value B is set in the normal equation shown by equation (34) for3×3 pixels located close to the designated pixel, thereby obtainingequations (35) through (43).

$\begin{matrix}\begin{matrix}{M_{{- 1},{- 1}} = {{\left( {- 1} \right) \cdot B_{{- 1},{- 1}} \cdot m} + {\left( {- 1} \right) \cdot B_{{- 1},{- 1}} \cdot q} +}} \\{{B_{{- 1},{- 1}} \cdot p} + {\left( {- 1} \right) \cdot s} + {\left( {- 1} \right) \cdot t} + u}\end{matrix} & (35) \\\begin{matrix}{M_{0,{- 1}} = {{(0) \cdot B_{0,{- 1}} \cdot m} + {\left( {- 1} \right) \cdot B_{0,{- 1}} \cdot q} +}} \\{{B_{0,{- 1}} \cdot p} + {(0) \cdot s} + {\left( {- 1} \right) \cdot t} + u}\end{matrix} & (36) \\\begin{matrix}{M_{{+ 1},{- 1}} = {{\left( {+ 1} \right) \cdot B_{{+ 1},{- 1}} \cdot m} + {\left( {- 1} \right) \cdot B_{{+ 1},{- 1}} \cdot q} +}} \\{{B_{{+ 1},{- 1}} \cdot p} + {\left( {+ 1} \right) \cdot s} + {\left( {- 1} \right) \cdot t} + u}\end{matrix} & (37) \\\begin{matrix}{M_{{- 1},0} = {{\left( {- 1} \right) \cdot B_{{- 1},0} \cdot m} + {(0) \cdot B_{{- 1},0} \cdot q} +}} \\{{B_{{- 1},0} \cdot p} + {\left( {- 1} \right) \cdot s} + {(0) \cdot t} + u}\end{matrix} & (38) \\\begin{matrix}{M_{0,0} = {{(0) \cdot B_{0,0} \cdot m} + {(0) \cdot B_{0,0} \cdot q} +}} \\{{B_{0,0} \cdot p} + {(0) \cdot s} + {(0) \cdot t} + u}\end{matrix} & (39) \\\begin{matrix}{M_{{+ 1},0} = {{\left( {+ 1} \right) \cdot B_{{+ 1},0} \cdot m} + {(0) \cdot B_{{+ 1},0} \cdot q} +}} \\{{B_{{+ 1},0} \cdot p} + {\left( {+ 1} \right) \cdot s} + {(0) \cdot t} + u}\end{matrix} & (40) \\\begin{matrix}{M_{{- 1},{+ 1}} = {{\left( {- 1} \right) \cdot B_{{- 1},{+ 1}} \cdot m} + {\left( {+ 1} \right) \cdot B_{{- 1},{+ 1}} \cdot q} +}} \\{{B_{{- 1},{+ 1}} \cdot p} + {\left( {- 1} \right) \cdot s} + {\left( {+ 1} \right) \cdot t} + u}\end{matrix} & (41) \\\begin{matrix}{M_{0,{+ 1}} = {{(0) \cdot B_{0,{+ 1}} \cdot m} + {\left( {- 1} \right) \cdot B_{0,{+ 1}} \cdot q} +}} \\{{B_{0,{+ 1}} \cdot p} + {(0) \cdot s} + {\left( {+ 1} \right) \cdot t} + u}\end{matrix} & (42) \\\begin{matrix}{{M +_{1,{+ 1}}} = {{\left( {+ 1} \right) \cdot B_{{+ 1},{+ 1}} \cdot m} + {\left( {+ 1} \right) \cdot B_{{+ 1},{+ 1}} \cdot q} +}} \\{{B_{{+ 1},{+ 1}} \cdot p} + {\left( {+ 1} \right) \cdot s} + {\left( {+ 1} \right) \cdot t} + u}\end{matrix} & (43)\end{matrix}$

Since the horizontal index j of the designated pixel is 0, and thevertical index k of the designated pixel is 0, the mixture ratio α ofthe designated pixel is equal to the value when j is 0 and k is 0 inequation (24), i.e., the mixture ratio α is equal to the intercept p inequation (24).

Accordingly, based on nine equations (35) through (43), the horizontalgradient m, the vertical gradient q, and the intercepts p, s, t, and uare calculated by the method of least squares, and the intercept p isoutput as the mixture ratio α.

A specific process for calculating the mixture ratio α by applying themethod of least squares is as follows.

When the index i and the index k are expressed by a single index x, therelationship among the index i, the index k, and the index x can beexpressed by equation (44).x=(j+1)·3+(k+1)  (44)

It is now assumed that the horizontal gradient m, the vertical gradientq, and the intercepts p, s, t, and u are expressed by variables w0, w1,w2, w3, w4, and W5, respectively, and jB, kB, B, j, k and l areexpressed by a0, a1, a2, a3, a4, and a5, respectively. In considerationof the error ex, equations (35) through (43) can be modified intoequation (45).

$\begin{matrix}{{M\; x} = {{\sum\limits_{y = 0}^{5}{{ay} \cdot {wy}}} + {ex}}} & (45)\end{matrix}$

In equation (45), x is any one of the integers from 0 to 28.

Equation (46) can be found from equation (45).

$\begin{matrix}{{ex} = {{M\; x} - {\sum\limits_{y = 0}^{5}{{ay} \cdot {wy}}}}} & (46)\end{matrix}$

Since the method of least squares is applied, the square sum E of theerror is defined as follows, as expressed by equation (47).

$\begin{matrix}{E = {\sum\limits_{x = 0}^{8}{ex}^{2}}} & (47)\end{matrix}$

In order to minimize the error, the partial differential value of thevariable Wv with respect to the square sum E of the error should be 0. vis any one of the integers from 0 to 5. Thus, wy is determined so thatequation (48) is satisfied.

$\begin{matrix}\begin{matrix}{\frac{\partial E}{\partial{Wv}} = {2 \cdot {\sum\limits_{x = 0}^{8}{{ex} \cdot \frac{\partial{ex}}{\partial{Wv}}}}}} \\{= {{2 \cdot {\sum\limits_{x = 0}^{8}{{ex} \cdot {av}}}} = 0}}\end{matrix} & (48)\end{matrix}$

By substituting equation (46) into equation (48), equation (49) isobtained.

$\begin{matrix}{{\sum\limits_{x = 0}^{8}\left( {{av} \cdot {\sum\limits_{y = 0}^{5}{{ay} \cdot {Wy}}}} \right)} = {\sum\limits_{x = 0}^{8}{{{av} \cdot M}\; x}}} & (49)\end{matrix}$

For example, the sweep-out method (Gauss-Jordan elimination) is appliedto six equations obtained by substituting one of the integers from 0 to5 into v in equation (49), thereby obtaining wy. As stated above, w0 isthe horizontal gradient m, w1 is the vertical gradient q, w2 is theintercept p, w3 is s, w4 is t, and w5 is u.

As discussed above, by applying the method of least squares to theequations in which the pixel value M and the pixel value B are set, thehorizontal gradient m, the vertical gradient q, and the intercepts p, s,t, and u can be determined.

A description has been given with reference to equations (35) through(43), by assuming that the pixel value of the pixel contained in themixed area is M, and the pixel value of the pixel contained in thebackground area is B. In this case, it is necessary to set normalequations for each of the cases where the designated pixel is containedin the covered background area, or the designated pixel is contained inthe uncovered background area.

For example, when the mixture ratio α of the pixel contained in thecovered background area in frame #n shown in FIG. 56 is determined, C04through C08 of the pixels in frame #n and the pixel values P04 throughP08 of the pixels in frame #n−1 are set in the normal equations.

For determining the mixture ratio α of the pixel contained in theuncovered background area in frame #n shown in FIG. 57, the pixels C28through C32 of frame #n and the pixel values N28 through N32 of thepixels in frame #n+1 are set in the normal equations.

Moreover, if, for example, the mixture ratio α of the pixel contained inthe covered background area shown in FIG. 67 is calculated, thefollowing equations (50) through (58) are set. The pixel value of thepixel for which the mixture ratio α is calculated is Mc5. In FIG. 67,the white dots indicate pixels to belong to the background, and theblack dots indicate pixels to belong to the mixed area.Mc1=(−1)·Bc1·m+(−1)·Bc1·q+Bc1·p+(−1)·s+(−1)·t+u  (50)Mc2=(0)·Bc2·m+(−1)·Bc2·q+Bc2·p+(0)·s+(−1)·t+u  (51)Mc3=(+1)·Bc3·m+(−1)·Bc3·q+Bc3·p+(+1)·s+(−1)·t+u  (52)Mc4=(−1)·Bc4·m+(0)·Bc4·q+Bc4·p+(−1)·s+(0)·t+u  (53)Mc5=(0)·Bc5·m+(0)·Bc5·q+Bc5·p+(0)·s+(0)·t+u  (54)Mc6=(+1)·Bc6·m+(0)·Bc6·q+Bc6·p+(+1)·s+(0)·t+u  (55)Mc7=(−1)·Bc7·m+(+1)·Bc7·q+Bc7·p+(−1)·s+(+1)·t+u  (56)Mc8=(0)·Bc8·m+(+1)·Bc8·q+Bc8·p+(0)·s+(+1)·t+u  (57)Mc9=(+1)·Bc9·m+(+1)·Bc9·q+Bc9·p+(+1)·s+(+1)·t+u  (58)

When calculating the mixture ratio α of the pixel contained in thecovered background area in frame #n, the pixel values Bc1 through Bc9 ofthe pixels in the background area in frame #n−1 corresponding to thepixels in frame #n are used in equations (50) through (58).

When, for example, the mixture ratio α of the pixel contained in theuncovered background area shown in FIG. 67 is calculated, the followingequations (59) through (67) are set. The pixel value of the pixel forwhich the mixture ratio α is calculated is Mu5.Mu1=(−1)·Bu1·m+(−1)·Bu1·q+Bu1·p+(−1)·s+(−1)·t+u  (59)Mu2=(0)·Bu2·m+(−1)·Bu2·q+Bu2·p+(0)·s+(−1)·t+u  (60)Mu3=(+1)·Bu3·m+(−1)·Bu3·q+Bu3·p+(+1)·s+(−1)·t+u  (61)Mu4=(−1)·Bu4·m+(0)·Bu4·q+Bu4·p+(−1)·s+(0)·t+u  (62)Mu5=(0)·Bu5·m+(0)·Bu5·q+Bu5·p+(0)·s+(0)·t+u  (63)Mu6=(+1)·Bu6·m+(0)·Bu6·q+Bu6·p+(+1)·s+(0)·t+u  (64)Mu7=(−1)·Bu7·m+(+1)·Bu7·q+Bu7·p+(−1)·s+(+1)·t+u  (65)Mu8=(0)·Bu8·m+(+1)·Bu8·q+Bu8·p+(0)·s+(+1)·t+u  (66)Mu9=(+1)·Bu9·m+(+1)·Bu9·q+Bu9·p+(+1)·s+(+1)·t+u  (67)

When calculating the mixture ratio α of the pixel contained in theuncovered background area in frame #n, the pixel values Bu1 through Bu9of the pixels of the background area in frame #n+1 corresponding to thepixels of frame #n are used in equations (59) through (67).

FIG. 68 is a block diagram illustrating the configuration of theestimated-mixture-ratio processor 401. An image input into theestimated-mixture-ratio processor 401 is supplied to a delay circuit 501and an adder 502.

The delay circuit 501 delays the input image for one frame, and suppliesthe image to the adder 502. When frame #n is supplied as the input imageto the adder 502, the delay circuit 501 supplies frame #n−1 to the adder502.

The adder 502 sets the pixel value of the pixel adjacent to the pixelfor which the mixture ratio α is calculated, and the pixel value offrame #n−1 in the normal equation. For example, the adder 502 sets thepixel values Mc1 through Mc9 and the pixel values Bc1 through Bc9 in thenormal equations based on equations (50) through (58), respectively. Theadder 502 supplies the normal equations in which the pixel values areset to a calculator 503.

Using the sweep-out method or the like, the calculator 503 determinesthe estimated mixture ratio by solving the normal equations suppliedfrom the adder 502, and outputs the determined estimated mixture ratio.

In this manner, the estimated-mixture-ratio processor 401 is able tocalculate the estimated mixture ratio based on the input image, andsupplies it to the mixture-ratio determining portion 403.

The estimated-mixture-ratio processor 402 is configured similar to theestimated-mixture-ratio processor 401, and an explanation thereof isthus omitted.

FIG. 69 illustrates an example of an estimated mixture ratio calculatedby the estimated-mixture-ratio processor 401. The estimated mixtureratio shown in FIG. 69 indicates the calculation result, with respect toone line, obtained by generating and calculating an equation in units of7×7-pixel blocks in which the amount of motion v in the foregroundcorresponding to an object moving at a constant speed is 11.

FIG. 68 shows that the estimated mixture ratio changes substantiallylinearly in the mixed area.

A description is now given, with reference to the flowchart of FIG. 70,of the mixture-ratio estimating processing by theestimated-mixture-ratio processor 401 having the configuration shown inFIG. 68 by using a model of the covered background area.

In step S521, the adder 502 sets the pixel value contained in the inputimage and the pixel value contained in the image supplied from the delaycircuit 501 in a normal equation corresponding to a model of the coveredbackground area.

In step S522, the estimated-mixture-ratio processor 401 determineswhether the setting of the designated pixels is finished. If it isdetermined that the setting of the designated pixels is not finished,the process returns to step S521, and the processing for setting thepixel values in the normal equation is repeated.

If it is determined in step S522 that the setting for the designatedpixels is finished, the process proceeds to step S523. In step S523, acalculator 173 calculates the estimated mixture ratio based on thenormal equations in which the pixels values are set, and outputs thecalculated mixture ratio.

As discussed above, the estimated-mixture-ratio processor 401 having theconfiguration shown in FIG. 68 is able to calculate the estimatedmixture ratio based on the input image.

The mixture-ratio estimating processing by using a model correspondingto the uncovered background area is similar to the processing indicatedby the flowchart of FIG. 70 by using the normal equations correspondingto a model of the uncovered background area, and an explanation thereofis thus omitted.

The embodiment has been described, assuming that the objectcorresponding to the background is stationary. However, theabove-described mixture-ratio calculation processing can be applied evenif the image corresponding to the background area contains motion. Forexample, if the image corresponding to the background area is uniformlymoving, the estimated-mixture-ratio processor 401 shifts the overallimage in accordance with this motion, and performs processing in amanner similar to the case in which the object corresponding to thebackground is stationary. If the image corresponding to the backgroundarea contains locally different motions, the estimated-mixture-ratioprocessor 401 selects the pixels corresponding to the motions as thepixels belonging to the mixed area, and executes the above-describedprocessing.

As described above, the mixture-ratio calculator 102 is able tocalculate the mixture ratio α, which is a feature quantity correspondingto each pixel, based on the input image and the area informationsupplied to the area specifying unit 101.

By utilizing the mixture ratio α, it is possible to separate theforeground components and the background components contained in thepixel values while maintaining the information of motion blur containedin the image corresponding to the moving object.

By combining the images based on the mixture ratio α, it is alsopossible to create an image which contains correct motion blur thatcoincides with the speed of a moving object and which faithfullyreflects the real world.

The foreground/background separator 105 is discussed below. FIG. 71 is ablock diagram illustrating an example of the configuration of theforeground/background separator 105. The input image supplied to theforeground/background separator 105 is supplied to a separating portion601, a switch 602, and a switch 604. The area information supplied fromthe area specifying unit 103 and indicating the information of thecovered background area and the uncovered background area is supplied tothe separating portion 601. The area information indicating theforeground area is supplied to the switch 602. The area informationindicating the background area supplied to the switch 604.

The mixture ratio α supplied from the mixture-ratio calculator 104 issupplied to the separating portion 601.

The separating portion 601 separates the foreground components from theinput image based on the area information indicating the coveredbackground area, the area information indicating the uncoveredbackground area, and the mixture ratio α, and supplies the separatedforeground components to a synthesizer 603. The separating portion 601also separates the background components from the input image, andsupplies the separated background components to a synthesizer 605.

The switch 602 is closed when a pixel corresponding to the foreground isinput based on the area information indicating the foreground area, andsupplies only the pixels corresponding to the foreground contained inthe input image to the synthesizer 603.

The switch 604 is closed when a pixel corresponding to the background isinput based on the area information indicating the background area, andsupplies only the pixels corresponding to the background contained inthe input image to the synthesizer 605.

The synthesizer 603 synthesizes a foreground component image based onthe foreground components supplied from the separating portion 601 andthe pixels corresponding to the foreground supplied from the switch 602,and outputs the synthesized foreground component image. Since theforeground area and the mixed area do not overlap, the synthesizer 603applies, for example, logical OR to the foreground components and theforeground pixels, thereby synthesizing the foreground component image.

In the initializing processing executed at the start of the synthesizingprocessing for the foreground component image, the synthesizer 603stores an image whose pixel values are all 0 in a built-in frame memory.Then, in the synthesizing processing for the foreground component image,the synthesizer 603 stores the foreground component image (overwritesthe previous image by the foreground component image). Accordingly, 0 isstored in the pixels corresponding to the background area in theforeground component image output from the synthesizer 603.

The synthesizer 605 synthesizes a background component image based onthe background components supplied from the separating portion 601 andthe pixels corresponding to the background supplied from the switch 604,and outputs the synthesized background component image. Since thebackground area and the mixed area do not overlap, the synthesizer 605applies, for example, logical OR to the background components and thebackground pixels, thereby synthesizing the background component image.

In the initializing processing executed at the start of the synthesizingprocessing for the background component image, the synthesizer 605stores an image whose pixel values are all 0 in a built-in frame memory.Then, in the synthesizing processing for the background component image,the synthesizer 605 stores the background component image (overwritesthe previous image by the background component image). Accordingly, 0 isstored in the pixels corresponding to the foreground area in thebackground component image output from the synthesizer 605.

FIGS. 72A and 72B illustrate the input image input into theforeground/background separator 105 and the foreground component imageand the background component image output from the foreground/backgroundseparator 105.

FIG. 72A is a schematic diagram illustrating the image to be displayed,and FIG. 72B is a model obtained by expanding in the time direction thepixels disposed in one line including the pixels belonging to theforeground area, the pixels belonging to the background area, and thepixels belonging to the mixed area corresponding to FIG. 72A.

As shown in FIGS. 72A and 72B, the background component image outputfrom the foreground/background separator 105 consists of the pixelsbelonging to the background area and the background components containedin the pixels of the mixed area.

As shown in FIGS. 72A and 72B, the foreground component image outputfrom the foreground/background separator 105 consists of the pixelbelonging to the foreground area and the foreground components containedin the pixels of the mixed area.

The pixel values of the pixels in the mixed area are separated into thebackground components and the foreground components by theforeground/background separator 105. The separated background componentsform the background component image together with the pixels belongingto the background area. The separated foreground components form theforeground component image together with the pixels belonging to theforeground area.

As discussed above, in the foreground component image, the pixel valuesof the pixels corresponding to the background area are set to 0, andsignificant pixel values are set in the pixels corresponding to theforeground area and the pixels corresponding to the mixed area.Similarly, in the background component image, the pixel values of thepixels corresponding to the foreground area are set to 0, andsignificant pixel values are set in the pixels corresponding to thebackground area and the pixels corresponding to the mixed area.

A description is given below of the processing executed by theseparating portion 601 for separating the foreground components and thebackground components from the pixels belonging to the mixed area.

FIG. 73 illustrates a model of an image indicating foreground componentsand background components in two frames including a foreground objectmoving from the left to the right in FIG. 73. In the model of the imageshown in FIG. 73, the amount of movement v is 4, and the number ofvirtual divided portions is 4.

In frame #n, the leftmost pixel and the fourteenth through eighteenthpixels from the left consist of only the background components andbelong to the background area. In frame #n, the second through fourthpixels from the left contain the background components and theforeground components, and belong to the uncovered background area. Inframe #n, the eleventh through thirteenth pixels from the left containbackground components and foreground components, and belong to thecovered background area. In frame #n, the fifth through tenth pixelsfrom the left consist of only the foreground components, and belong tothe foreground area.

In frame #n+1, the first through fifth pixels from the left and theeighteenth pixel from the left consist of only the backgroundcomponents, and belong to the background area. In frame #n+1, the sixththrough eighth pixels from the left contain background components andforeground components, and belong to the uncovered background area. Inframe #n+1, the fifteenth through seventeenth pixels from the leftcontain background components and foreground components, and belong tothe covered background area. In frame #n+1, the ninth through fourteenthpixels from the left consist of only the foreground components, andbelong to the foreground area.

FIG. 74 illustrates the processing for separating the foregroundcomponents from the pixels belonging to the covered background area. InFIG. 74, α1 through α18 indicate mixture ratios of the individual pixelsof frame #n. In FIG. 74, the fifteenth through seventeenth pixels fromthe left belong to the covered background area.

The pixel value C15 of the fifteenth pixel from the left in frame #n canbe expressed by equation (68):

$\begin{matrix}\begin{matrix}{{C15} = {{{B15}/v} + {{F09}/v} + {{F08}/v} + {{F07}/v}}} \\{= {{\alpha\;{15 \cdot {B15}}} + {{F09}/v} + {{F08}/v} + {{F07}/v}}} \\{= {{\alpha\;{15 \cdot {P15}}} + {{F09}/v} + {{F08}/v} + {{F07}/v}}}\end{matrix} & (68)\end{matrix}$

where α15 indicates the mixture ratio of the fifteenth pixel from theleft in frame #n, and P15 designates the pixel value of the fifteenthpixel from the left in frame #n−1.

The sum f15 of the foreground components of the fifteenth pixel from theleft in frame #n can be expressed by equation (69) based on equation(68).

$\begin{matrix}\begin{matrix}{{f15} = {{{F09}/v} + {{F08}/v} + {{F07}/v}}} \\{= {{C15} - {\alpha\;{15 \cdot {P15}}}}}\end{matrix} & (69)\end{matrix}$

Similarly, the sum f16 of the foreground components of the sixteenthpixel from the left in frame #n can be expressed by equation (70), andthe sum f17 of the foreground components of the seventeenth pixel fromthe left in frame #n can be expressed by equation (71).f16=C16−α16·P16  (70)f17=C17−α17·P17  (71)

In this manner, the foreground components fc contained in the pixelvalue C of the pixel belonging to the covered background area can beexpressed by equation (72):fc=C−α·P  (72)

where P designates the pixel value of the corresponding pixel in theprevious frame.

FIG. 75 illustrates the processing for separating the foregroundcomponents from the pixels belonging to the uncovered background area.In FIG. 75, α1 through α18 indicate mixture ratios of the individualpixels of frame #n. In FIG. 75, the second through fourth pixels fromthe left belong to the uncovered background area.

The pixel value C02 of the second pixel from the left in frame #n can beexpressed by equation (73):C02=B02/v+B02/v+B02/v+F01/v=α2·B02+F01/v=α2·N02+F01/v  (73)

where α2 indicates the mixture ratio of the second pixel from the leftin frame #n, and N02 designates the pixel value of the second pixel fromthe left in frame #n+1.

The sum f02 of the foreground components of the second pixel from theleft in frame #n can be expressed by equation (74) based on equation(73).f02=F01/v=C02−α2·N02  (74)

Similarly, the sum f03 of the foreground components of the third pixelfrom the left in frame #n can be expressed by equation (75), and the sumf04 of the foreground components of the fourth pixel from the left inframe #n can be expressed by equation (76).f03=C03−α3·N03  (75)f04=C04−α4·N04  (76)

In this manner, the foreground components fu contained in the pixelvalue C of the pixel belonging to the uncovered background area can beexpressed by equation (77)fu=C−α·N  (77)

where N designates the pixel value of the corresponding pixel in thesubsequent frame.

As discussed above, the separating portion 601 is able to separate theforeground components from the pixels belonging to the mixed area andthe background components from the pixels belonging to the mixed areabased on the information indicating the covered background area and theinformation indicating the uncovered background area contained in thearea information, and the mixture ratio α for each pixel.

FIG. 76 is a block diagram illustrating an example of the configurationof the separating portion 601 for executing the above-describedprocessing. An image input into the separating portion 601 is suppliedto a frame memory 621, and the area information indicating the coveredbackground area and the uncovered background area supplied from themixture-ratio calculator 104 and the mixture ratio α are supplied to aseparation processing block 622.

The frame memory 621 stores the input images in units of frames. When aframe to be processed is frame #n, the frame memory 621 stores frame#n−1, which is the frame one frame before frame #n, frame #n, and frame#n+1, which is the frame one frame after frame #n.

The frame memory 621 supplies the corresponding pixels in frame #n−1,frame #n, and frame #n+1 to the separation processing block 622.

The separation processing block 622 applies the calculations discussedwith reference to FIGS. 74 and 75 to the pixel values of thecorresponding pixels in frame #n−1, frame #n, and frame #n+1 suppliedfrom the frame memory 621 based on the area information indicating thecovered background area and the uncovered background area and themixture ratio α so as to separate the foreground components and thebackground components from the pixels belonging to the mixed area inframe #n, and supplies them to a frame memory 623.

The separation processing block 622 is formed of an uncovered areaprocessor 631, a covered area processor 632, a synthesizer 633, and asynthesizer 634.

A multiplier 641 of the uncovered area processor 631 multiplies thepixel value of the pixel in frame #n+1 supplied from the frame memory621 by the mixture ratio α, and outputs the resulting pixel value to aswitch 642. The switch 642 is closed when the pixel of frame #n(corresponding to the pixel in frame #n+1) supplied from the framememory 621 belongs to the uncovered background area, and supplies thepixel value multiplied by the mixture ratio α supplied from themultiplier 641 to a calculator 643 and the synthesizer 634. The valueobtained by multiplying the pixel value of the pixel in frame #n+1 bythe mixture ratio α output from the switch 642 is equivalent to thebackground components of the pixel value of the corresponding pixel inframe #n.

The calculator 643 subtracts the background components supplied from theswitch 642 from the pixel value of the pixel in frame #n supplied fromthe frame memory 621 so as to obtain the foreground components. Thecalculator 643 supplies the foreground components of the pixel in frame#n belonging to the uncovered background area to the synthesizer 633.

A multiplier 651 of the covered area processor 632 multiplies the pixelvalue of the pixel in frame #n−1 supplied from the frame memory 621 bythe mixture ratio α, and outputs the resulting pixel value to a switch652. The switch 652 is closed when the pixel of frame #n (correspondingto the pixel in frame #n−1) supplied from the frame memory 621 belongsto the covered background area, and supplies the pixel value multipliedby the mixture ratio α supplied from the multiplier 651 to a calculator653 and the synthesizer 634. The value obtained by multiplying the pixelvalue of the pixel in frame #n−1 by the mixture ratio α output from theswitch 652 is equivalent to the background components of the pixel valueof the corresponding pixel in frame #n.

The calculator 653 subtracts the background components supplied from theswitch 652 from the pixel value of the pixel in frame #n supplied fromthe frame memory 621 so as to obtain the foreground components. Thecalculator 653 supplies the foreground components of the pixel in frame#n belonging to the covered background area to the synthesizer 633.

The synthesizer 633 combines the foreground components of the pixelsbelonging to the uncovered background area and supplied from thecalculator 643 with the foreground components of the pixels belonging tothe covered background area and supplied from the calculator 653, andsupplies the synthesized foreground components to the frame memory 623.

The synthesizer 634 combines the background components of the pixelsbelonging to the uncovered background area and supplied from the switch642 with the background components of the pixels belonging to thecovered background area and supplied from the switch 652, and suppliesthe synthesized background components to the frame memory 623.

The frame memory 623 stores the foreground components and the backgroundcomponents of the pixels in the mixed area of frame #n supplied from theseparation processing block 622.

The frame memory 623 outputs the stored foreground components of thepixels in the mixed area in frame #n and the stored backgroundcomponents of the pixels in the mixed area in frame #n.

By utilizing the mixture ratio α, which indicates the feature quantity,the foreground components and the background components contained in thepixel values can be completely separated.

The synthesizer 603 combines the foreground components of the pixels inthe mixed area in frame #n output from the separating portion 601 withthe pixels belonging to the foreground area so as to generate aforeground component image. The synthesizer 605 combines the backgroundcomponents of the pixels in the mixed area in frame #n output from theseparating portion 601 with the pixels belonging to the background areaso as to generate a background component image.

FIGS. 77A and 77B illustrate an example of the foreground componentimage and an example of the background component image corresponding toframe #n in FIG. 73.

FIG. 77A illustrates the example of the foreground component imagecorresponding to frame #n in FIG. 73. The leftmost pixel and thefourteenth pixel from the left consist of only the background componentsbefore the foreground and the background are separated, and thus, thepixel values are set to 0.

The second and fourth pixels from the left belong to the uncoveredbackground area before the foreground and the background are separated.Accordingly, the background components are set to 0, and the foregroundcomponents are maintained. The eleventh through thirteenth pixels fromthe left belong to the covered background area before the foreground andthe background are separated. Accordingly, the background components areset to 0, and the foreground components are maintained. The fifththrough tenth pixels from the left consist of only the foregroundcomponents, which are thus maintained.

FIG. 77B illustrates the example of the background component imagecorresponding to frame #n in FIG. 73. The leftmost pixel and thefourteenth pixel from the left consist of only the background componentsbefore the foreground and the background are separated, and thus, thebackground components are maintained.

The second through fourth pixels from the left belong to the uncoveredbackground area before the foreground and the background are separated.Accordingly, the foreground components are set to 0, and the backgroundcomponents are maintained. The eleventh through thirteenth pixels fromthe left belong to the covered background area before the foreground andthe background are separated. Accordingly, the foreground components areset to 0, and the background components are maintained. The fifththrough tenth pixels from the left consist of only the foregroundcomponents, and thus, the pixel values are set to 0.

The processing for separating the foreground and the background executedby the foreground/background separator 105 is described below withreference to the flowchart of FIG. 78. In step S601, the frame memory621 of the separating portion 601 obtains an input image, and storesframe #n for which the foreground and the background are separatedtogether with the previous frame #n−1 and the subsequent frame #n+1.

In step S602, the separation processing block 622 of the separatingportion 601 obtains area information supplied from the mixture-ratiocalculator 104. In step S603, the separation processing block 622 of theseparating portion 601 obtains the mixture ratio α supplied from themixture-ratio calculator 104.

In step S604, the uncovered area processor 631 extracts the backgroundcomponents from the pixel values of the pixels belonging to theuncovered background area supplied from the frame memory 621 based onthe area information and the mixture ratio α.

In step S605, the uncovered area processor 631 extracts the foregroundcomponents from the pixel values of the pixels belonging to theuncovered background area supplied from the frame memory 621 based onthe area information and the mixture ratio α.

In step S606, the covered area processor 632 extracts the backgroundcomponents from the pixel values of the pixels belonging to the coveredbackground area supplied from the frame memory 621 based on the areainformation and the mixture ratio α.

In step S607, the covered area processor 632 extracts the foregroundcomponents from the pixel values of the pixels belonging to the coveredbackground area supplied from the frame memory 621 based on the areainformation and the mixture ratio α.

In step S608, the synthesizer 633 combines the foreground components ofthe pixels belonging to the uncovered background area extracted in theprocessing of step S605 with the foreground components of the pixelsbelonging to the covered background area extracted in the processing ofstep S607. The synthesized foreground components are supplied to thesynthesizer 603. The synthesizer 603 further combines the pixelsbelonging to the foreground area supplied via the switch 602 with theforeground components supplied from the separating portion 601 so as togenerate a foreground component image.

In step S609, the synthesizer 634 combines the background components ofthe pixels belonging to the uncovered background area extracted in theprocessing of step S604 with the background components of the pixelsbelonging to the covered background area extracted in the processing ofstep S606. The synthesized background components are supplied to thesynthesizer 605. The synthesizer 605 further combines the pixelsbelonging to the background area supplied via the switch 604 with thebackground components supplied from the separating portion 601 so as togenerate a background component image.

In step S610, the synthesizer 603 outputs the foreground componentimage. In step S611, the synthesizer 605 outputs the backgroundcomponent image. The processing is then completed.

As discussed above, the foreground/background separator 105 is able toseparate the foreground components and the background components fromthe input image based on the area information and the mixture ratio α,and outputs the foreground component image consisting of only theforeground components and the background component image consisting ofonly the background components.

Adjustments of the amount of motion blur in a foreground component imageare described below.

FIG. 79 is a block diagram illustrating an example of the configurationof the motion-blur adjusting unit 106. The motion vector and thepositional information thereof supplied from the motion detector 102 aresupplied to a unit-of-processing determining portion 801, amodel-forming portion 802, and a calculator 805. The area informationsupplied from the area specifying unit 103 is supplied to theunit-of-processing determining portion 801. The area informationsupplied from the foreground/background separator 105 is supplied to anadder 804.

The unit-of-processing determining portion 801 generates the unit ofprocessing based on the motion vector, the positional informationthereof, and the area information and supplies the generated unit ofprocessing to the model-forming portion 802 and the adder 804.

As shown by an example in FIG. 80, the unit of processing A generated bythe unit-of-processing determining portion 801 indicates consecutivepixels disposed in the moving direction starting from the pixelcorresponding to the covered background area of the foreground componentimage until the pixel corresponding to the uncovered background area, orindicates consecutive pixels disposed in the moving direction startingfrom the pixel corresponding to the uncovered background area until thepixel corresponding to the covered background area. The unit ofprocessing A is formed of two pieces of data which indicate, forexample, the upper left point (which is the position of the leftmost orthe topmost pixel in the image designated by the unit of processing A)and the lower right point.

The model-forming portion 802 forms a model based on the motion vectorand the input unit of processing A. More specifically, for example, themodel-forming portion 802 may store in advance a plurality of models inaccordance with the number of pixels contained in the unit of processingA, the number of virtual divided portions of the pixel value in the timedirection, and the number of foreground components for each pixel. Themodel-forming portion 802 selects the model in which the correlationbetween the pixel values and the foreground components is designated,such as that in FIG. 81, based on the unit of processing A and thenumber of virtual divided portions of the pixel value in the timedirection.

It is now assumed, for example, that the number of pixels correspondingto the unit of processing A is 12, and that the amount of movement vwithin the shutter time is 5. Then, the model-forming portion 802 setsthe number of virtual divided portions to 5, and selects a model formedof eight types of foreground components so that the leftmost pixelcontains one foreground component, the second pixel from the leftcontains two foreground components, the third pixel from the leftcontains three foreground components, the fourth pixel from the leftcontains four pixel components, the fifth pixel from the left containsfive foreground components, the sixth pixel from the left contains fiveforeground components, the seventh pixel from the left contains fiveforeground components, the eighth pixel from the left contains fiveforeground components, the ninth pixel from the left contains fourforeground components, the tenth pixel from the left contains threeforeground components, the eleventh pixel from the left contains twoforeground components, and the twelfth pixel from the left contains oneforeground component.

Instead of selecting a model from the prestored models, themodel-forming portion 802 may generate a model based on the motionvector and the unit of processing A when the motion vector and the unitof processing A are supplied.

The model-forming portion 802 supplies the selected model to an equationgenerator 803.

The equation generator 803 generates an equation based on the modelsupplied from the model-forming portion 802. A description is givenbelow, with reference to the model of the foreground component imageshown in FIG. 81, of equations generated by the equation generator 803when the number of foreground components is 8, the number of pixelscorresponding to the unit of processing A is 12, and the amount ofmovement v is 5.

When the foreground components contained in the foreground componentimage corresponding to the shutter time/v are F01/v through F08/v, therelationships between F01/v through F08/v and the pixel values C01through C12 can be expressed by equations (78) through (89).C01=F01/v  (78)C02=F02/v+F01/v  (79)C03=F03/v+F02/v+F01v  (80)C04=F04/v+F03/v+F02/v+F01v  (81)C05=F05/v+F04/v+F03/v+F02/v+F01v  (82)C06=F06/v+F05/v+F04/v+F03/v+F02/v  (83)C07=F07/v+F06/v+F05/v+F04/v+F03/v  (84)C08=F08/v+F07/v+F06/v+F05/v+F04/v  (85)C09=F08/v+F07/v+F06/v+F05/v  (86)C10=F08/v+F07/v+F06/v  (87)C11=F08/v+F07/v  (88)C12=F08/v  (89)

The equation generator 803 generates an equation by modifying thegenerated equations. The equations generated by the equation generator803 are indicated by equations (90) though (101).

$\begin{matrix}\begin{matrix}{{C01} = {{1 \cdot {{F01}/v}} + {0 \cdot {{F02}/v}} + {0 \cdot {{F03}/v}} + {0 \cdot {{F04}/v}} +}} \\{{0 \cdot {{F05}/v}} + {0 \cdot {{F06}/v}} + {0 \cdot {{F07}/v}} + {0 \cdot {{F08}/v}}}\end{matrix} & (90) \\\begin{matrix}{{C02} = {{1 \cdot {{F01}/v}} + {1 \cdot {{F02}/v}} + {0 \cdot {{F03}/v}} + {0 \cdot {{F04}/v}} +}} \\{{0 \cdot {{F05}/v}} + {0 \cdot {{F06}/v}} + {0 \cdot {{F07}/v}} + {0 \cdot {{F08}/v}}}\end{matrix} & (91) \\\begin{matrix}{{C03} = {{1 \cdot {{F01}/v}} + {1 \cdot {{F02}/v}} + {1 \cdot {{F03}/v}} + {0 \cdot {{F04}/v}} +}} \\{{0 \cdot {{F05}/v}} + {0 \cdot {{F06}/v}} + {0 \cdot {{F07}/v}} + {0 \cdot {{F08}/v}}}\end{matrix} & (92) \\\begin{matrix}{{C04} = {{1 \cdot {{F01}/v}} + {1 \cdot {{F02}/v}} + {1 \cdot {{F03}/v}} + {1 \cdot {{F04}/v}} +}} \\{{0 \cdot {{F05}/v}} + {0 \cdot {{F06}/v}} + {0 \cdot {{F07}/v}} + {0 \cdot {{F08}/v}}}\end{matrix} & (93) \\\begin{matrix}{{C05} = {{1 \cdot {{F01}/v}} + {1 \cdot {{F02}/v}} + {1 \cdot {{F03}/v}} + {1 \cdot {{F04}/v}} +}} \\{{1 \cdot {{F05}/v}} + {0 \cdot {{F06}/v}} + {0 \cdot {{F07}/v}} + {0 \cdot {{F08}/v}}}\end{matrix} & (94) \\\begin{matrix}{{C06} = {{0 \cdot {{F01}/v}} + {1 \cdot {{F02}/v}} + {1 \cdot {{F03}/v}} + {1 \cdot {{F04}/v}} +}} \\{{1 \cdot {{F05}/v}} + {1 \cdot {{F06}/v}} + {0 \cdot {{F07}/v}} + {0 \cdot {{F08}/v}}}\end{matrix} & (95) \\\begin{matrix}{{C07} = {{0 \cdot {{F01}/v}} + {0 \cdot {{F02}/v}} + {1 \cdot {{F03}/v}} + {1 \cdot {{F04}/v}} +}} \\{{1 \cdot {{F05}/v}} + {1 \cdot {{F06}/v}} + {1 \cdot {{F07}/v}} + {0 \cdot {{F08}/v}}}\end{matrix} & (96) \\\begin{matrix}{{C08} = {{0 \cdot {{F01}/v}} + {0 \cdot {{F02}/v}} + {0 \cdot {{F03}/v}} + {1 \cdot {{F04}/v}} +}} \\{{1 \cdot {{F05}/v}} + {1 \cdot {{F06}/v}} + {1 \cdot {{F07}/v}} + {1 \cdot {{F08}/v}}}\end{matrix} & (97) \\\begin{matrix}{{C09} = {{0 \cdot {{F01}/v}} + {0 \cdot {{F02}/v}} + {0 \cdot {{F03}/v}} + {0 \cdot {{F04}/v}} +}} \\{{1 \cdot {{F05}/v}} + {1 \cdot {{F06}/v}} + {1 \cdot {{F07}/v}} + {1 \cdot {{F08}/v}}}\end{matrix} & (98) \\\begin{matrix}{{C10} = {{0 \cdot {{F01}/v}} + {0 \cdot {{F02}/v}} + {0 \cdot {{F03}/v}} + {0 \cdot {{F04}/v}} +}} \\{{0 \cdot {{F05}/v}} + {1 \cdot {{F06}/v}} + {1 \cdot {{F07}/v}} + {1 \cdot {{F08}/v}}}\end{matrix} & (99) \\\begin{matrix}{{C11} = {{0 \cdot {{F01}/v}} + {0 \cdot {{F02}/v}} + {0 \cdot {{F03}/v}} + {0 \cdot {{F04}/v}} +}} \\{{0 \cdot {{F05}/v}} + {0 \cdot {{F06}/v}} + {1 \cdot {{F07}/v}} + {1 \cdot {{F08}/v}}}\end{matrix} & (100) \\\begin{matrix}{{C12} = {{0 \cdot {{F01}/v}} + {0 \cdot {{F02}/v}} + {0 \cdot {{F03}/v}} + {0 \cdot {{F04}/v}} +}} \\{{0 \cdot {{F05}/v}} + {0 \cdot {{F06}/v}} + {0 \cdot {{F07}/v}} + {1 \cdot {{F08}/v}}}\end{matrix} & (101)\end{matrix}$

Equations (90) through (101) can be expressed by equation (102).

$\begin{matrix}{{Cj} = {\sum\limits_{i = 01}^{08}{{aij} \cdot {{Fi}/v}}}} & (102)\end{matrix}$

In equation (102), j designates the position of the pixel. In thisexample, j has one of the values from 1 to 12. In equation (102), idesignates the position of the foreground value. In this example, i hasone of the values from 1 to 8. In equation (102), aij has the value 0 or1 according to the values of i and j.

Equation (102) can be expressed by equation (103) in consideration ofthe error.

$\begin{matrix}{{Cj} = {{\sum\limits_{i = 01}^{08}{{aij} \cdot {{Fi}/v}}} + {ej}}} & (103)\end{matrix}$

In equation (103), ej designates the error contained in the designatedpixel Cj.

Equation (103) can be modified into equation (104).

$\begin{matrix}{{ej} = {{Cj} - {\sum\limits_{i = 01}^{08}{{aij} \cdot {{Fi}/v}}}}} & (104)\end{matrix}$

In order to apply the method of least squares, the square sum E of theerror is defined as equation (105).

$\begin{matrix}{E = {\sum\limits_{j = 01}^{12}{ej}^{2}}} & (105)\end{matrix}$

In order to minimize the error, the partial differential value using thevariable Fk with respect to the square sum E of the error should be 0.Fk is determined so that equation (106) is satisfied.

$\begin{matrix}\begin{matrix}{\frac{\partial E}{\partial{Fk}} = {2 \cdot {\sum\limits_{j = 01}^{12}{{ej} \cdot \frac{\partial{ej}}{\partial{Fk}}}}}} \\{= {2 \cdot {\sum\limits_{j = 01}^{12}\left\{ {{\left( {{Cj} - {\sum\limits_{i = 01}^{08}{{aij} \cdot {{Fi}/v}}}} \right) \cdot \left( {{- {akj}}/v} \right)} = 0} \right.}}}\end{matrix} & (106)\end{matrix}$

In equation (106), since the amount of movement v is a fixed value,equation (107) can be deduced.

$\begin{matrix}{{\sum\limits_{j = 01}^{12}{{akj} \cdot \left( {{Cj} - {\sum\limits_{i = 01}^{08}{{aij} \cdot {{Fi}/v}}}} \right)}} = 0} & (107)\end{matrix}$

To expand equation (107) and transpose the terms, equation (108) can beobtained.

$\begin{matrix}{{\sum\limits_{j = 01}^{12}\left( {{akj} \cdot {\sum\limits_{i = 01}^{08}{{aij} \cdot {Fi}}}} \right)} = {v{\sum\limits_{j = 01}^{12}{{akj} \cdot {Cj}}}}} & (108)\end{matrix}$

Equation (108) is expanded into eight equations by substituting theindividual integers from 1 to 8 into k in equation (108). The obtainedeight equations can be expressed by one matrix equation. This equationis referred to as a “normal equation”.

An example of the normal equation generated by the equation generator803 based on the method of least squares is indicated by equation (109).

$\begin{matrix}{{\begin{bmatrix}5 & 4 & 3 & 2 & 1 & 0 & 0 & 0 \\4 & 5 & 4 & 3 & 2 & 1 & 0 & 0 \\3 & 4 & 5 & 4 & 3 & 2 & 1 & 0 \\2 & 3 & 4 & 5 & 4 & 3 & 2 & 1 \\1 & 2 & 3 & 4 & 5 & 4 & 3 & 2 \\0 & 1 & 2 & 3 & 4 & 5 & 4 & 3 \\0 & 0 & 1 & 2 & 3 & 4 & 5 & 4 \\0 & 0 & 0 & 1 & 2 & 3 & 4 & 5\end{bmatrix}\begin{bmatrix}{F01} \\{F02} \\{F03} \\{F04} \\{F05} \\{F06} \\{F07} \\{F08}\end{bmatrix}} = {v \cdot \begin{bmatrix}{\sum\limits_{i = 08}^{12}{Ci}} \\{\sum\limits_{i = 07}^{11}{Ci}} \\{\sum\limits_{i = 06}^{10}{Ci}} \\{\sum\limits_{i = 05}^{09}{Ci}} \\{\sum\limits_{i = 04}^{08}{Ci}} \\{\sum\limits_{i = 03}^{07}{Ci}} \\{\sum\limits_{i = 02}^{06}{Ci}} \\{\sum\limits_{i = 01}^{05}{Ci}}\end{bmatrix}}} & (109)\end{matrix}$

When equation (109) is expressed by A·F=v·C, C, A, and v are known, andF is unknown. A and v are known when the model is formed, while Cbecomes known when the pixel value is input in the addition processing.

By calculating the foreground components according to the normalequation based on the method of least squares, the error contained inthe pixel C can be distributed.

The equation generator 803 supplies the normal equation generated asdiscussed above to the adder 804.

The adder 804 sets, based on the unit of processing supplied from theunit-of-processing determining portion 801, the pixel value C containedin the foreground component image in the matrix equation supplied fromthe equation generator 803. The adder 804 supplies the matrix in whichthe pixel value C is set to a calculator 805.

The calculator 805 calculates the foreground component Fi/v from whichmotion blur is eliminated by the processing based on a solution, such asa sweep-out method (Gauss-Jordan elimination), so as to obtain Ficorresponding to i indicating one of the integers from 1 to 8, which isthe pixel value from which motion blur is eliminated. The calculator 805then outputs the foreground component image consisting of the pixelvalues Fi without motion blur, such as that in FIG. 82, to a motion-bluradder 806 and a selector 807.

In the foreground component image without motion blur shown in FIG. 82,the reason for setting F01 through F08 in C03 through C10, respectively,is not to change the position of the foreground component image withrespect to the screen. However, F01 through F08 may be set in anydesired positions.

The motion-blur adder 806 is able to adjust the amount of motion blur byadding the amount v′ by which motion blur is adjusted, which isdifferent from the amount of movement v, for example, the amount v′ bywhich motion blur is adjusted, which is one half the value of the amountof movement v, or the amount v′ by which motion blur is adjusted, whichis irrelevant to the amount of movement v. For example, as shown in FIG.83, the motion-blur adder 806 divides the foreground pixel value Fiwithout motion blur by the amount v′ by which motion blur is adjusted soas to obtain the foreground component Fi/v′. The motion-blur adder 806then calculates the sum of the foreground components Fi/v′, therebygenerating the pixel value in which the amount of motion blur isadjusted. For example, when the amount v′ by which motion blur isadjusted is 3, the pixel value C02 is set to (F01)/v′, the pixel valueC3 is set to (F01+F02)/v′, the pixel value C04 is set to(F01+F02+F03)/v′, and the pixel value C05 is set to (F02+F03+F04)/v′.

The motion-blur adder 806 supplies the foreground component image inwhich the amount of motion blur is adjusted to a selector 807.

The selector 807 selects one of the foreground component image withoutmotion blur supplied from the calculator 805 and the foregroundcomponent image in which the amount of motion blur is adjusted suppliedfrom the motion-blur adder 806 based on a selection signal reflecting auser's selection, and outputs the selected foreground component image.

As discussed above, the motion-blur adjusting unit 106 is able to adjustthe amount of motion blur based on the selection signal and the amountv′ by which motion blur is adjusted.

Also, for example, when the number of pixels corresponding to the unitof processing is 8, and the amount of movement v is 4, as shown in FIG.84, the motion-blur adjusting unit 106 generates a matrix equationexpressed by equation (110).

$\begin{matrix}{{\begin{bmatrix}4 & 3 & 2 & 1 & 0 \\3 & 4 & 3 & 2 & 1 \\2 & 3 & 4 & 3 & 2 \\1 & 2 & 3 & 4 & 3 \\0 & 1 & 2 & 3 & 4\end{bmatrix}\begin{bmatrix}{F01} \\{F02} \\{F03} \\{F04} \\{F05}\end{bmatrix}} = {v \cdot \begin{bmatrix}{\sum\limits_{i = 05}^{08}{Ci}} \\{\sum\limits_{i = 04}^{07}{Ci}} \\{\sum\limits_{i = 03}^{06}{Ci}} \\{\sum\limits_{i = 02}^{05}{Ci}} \\{\sum\limits_{i = 01}^{04}{Ci}}\end{bmatrix}}} & (110)\end{matrix}$

In this manner, the motion-blur adjusting unit 106 calculates Fi, whichis the pixel value in which the amount of motion blur is adjusted, bysetting up the equation in accordance with the length of the unit ofprocessing. Similarly, for example, when the number of pixels containedin the unit of processing is 100, the equation corresponding to 100pixels is generated so as to calculate Fi.

FIG. 85 illustrates an example of another configuration of themotion-blur adjusting unit 106. The same elements as those shown in FIG.79 are designated with like reference numerals, and an explanationthereof is thus omitted.

Based on a selection signal, a selector 821 directly supplies an inputmotion vector and a positional signal thereof to the unit-of-processingdetermining portion 801 and the model-forming portion 802.Alternatively, the selector 821 may substitute the magnitude of themotion vector by the amount v′ by which motion blur is adjusted, andthen supplies the motion vector and the positional signal thereof to theunit-of-processing determining portion 801 and the model-forming unit802.

With this arrangement, the unit-of-processing determining portion 801through the calculator 805 of the motion-blur adjusting unit 106 shownin FIG. 85 are able to adjust the amount of motion blur in accordancewith the amount of movement v and the amount v′ by which motion blur isadjusted. For example, when the amount of movement is 5, and the amountv′ by which motion blur is adjusted is 3, the unit-of-processingdetermining portion 801 through the calculator 805 of the motion-bluradjusting unit 106 shown in FIG. 85 execute computation on theforeground component image in which the amount of movement v is 5 shownin FIG. 81 according to the model shown in FIG. 83 in which the amountv′ by which motion blur is adjusted is 3. As a result, the imagecontaining motion blur having the amount of movement v of (amount ofmovement v)/(amount v′ by which motion blur is adjusted)= 5/3, i.e.,about 1.7 is obtained. In this case, the calculated image does notcontain motion blur corresponding to the amount of movement v of 3.Accordingly, it should be noted that the relationship between the amountof movement v and the amount v′ by which motion blur is adjusted isdifferent from the result of the motion-blur adder 806.

As discussed above, the motion-blur adjusting unit 106 generates theequation in accordance with the amount of movement v and the unit ofprocessing, and sets the pixel values of the foreground component imagein the generated equation, thereby calculating the foreground componentimage in which the amount of motion blur is adjusted.

The processing for adjusting the amount of motion blur contained in theforeground component image executed by the motion-blur adjusting unit106 is described below with reference to the flowchart of FIG. 86.

In step S801, the unit-of-processing determining portion 801 of themotion-blur adjusting unit 106 generates the unit of processing based onthe motion vector and the area information, and supplies the generatedunit of processing to the model-forming portion 802.

In step S802, the model-forming portion 802 of the motion-blur adjustingunit 106 selects or generates the model in accordance with the amount ofmovement v and the unit of processing. In step S803, the equationgenerator 803 generates the normal equation based on the selected model.

In step S804, the adder 804 sets the pixel values of the foregroundcomponent image in the generated normal equation. In step S805, theadder 804 determines whether the pixel values of all the pixelscorresponding to the unit of processing are set. If it is determinedthat the pixel values of all the pixels corresponding to the unit ofprocessing are not yet set, the process returns to step S804, and theprocessing for setting the pixel values in the normal equation isrepeated.

If it is determined in step S805 that the pixel values of all the pixelscorresponding to the unit of processing are set, the process proceeds tostep S806. In step S806, the calculator 805 calculates the pixel valuesof the foreground in which the amount of motion blur is adjusted basedon the normal equation in which the pixel values are set supplied fromthe adder 804. The processing is then completed.

As discussed above, the motion-blur adjusting unit 106 is able to adjustthe amount of motion blur of the foreground image containing motion blurbased on the motion vector and the area information.

That is, it is possible to adjust the amount of motion blur contained inthe pixel values, that is, contained in sampled data.

FIG. 87 is a block diagram illustrating another example of theconfiguration of the motion-blur adjusting unit 106. The motion vectorand the positional information thereof supplied from the motion detector102 are supplied to a unit-of-processing determining portion 901 and anadjusting portion 905. The area information supplied from the areaspecifying unit 103 is supplied to the unit-of-processing determiningportion 901. The foreground component image supplied from theforeground/background separator 105 is supplied to a calculator 904.

The unit-of-processing determining portion 901 generates the unit ofprocessing on the basis of the motion vector, the positional informationthereof, and the area information and supplies the generated unit ofprocessing, together with the motion vector, to a model-forming portion902.

The model-forming portion 902 forms a model based on the motion vectorand the input unit of processing. More specifically, for example, themodel-forming portion 902 may store in advance a plurality of models inaccordance with the number of pixels contained in the unit ofprocessing, the number of virtual divided portions of the pixel value inthe time direction, and the number of foreground components for eachpixel. The model-forming portion 902 selects the model in which thecorrelation between the pixel values and the foreground components isdesignated, such as that in FIG. 88, based on the unit of processing andthe number of virtual divided portions of the pixel value in the timedirection.

It is now assumed, for example, that the number of pixels correspondingto the unit of processing is 12, and that the amount of movement v is 5.Then, the model-forming portion 902 sets the number of virtual dividedportions to 5, and selects a model formed of eight types of foregroundcomponents so that the leftmost pixel contains one foreground component,the second pixel from the left contains two foreground components, thethird pixel from the left contains three foreground components, thefourth pixel from the left contains four pixel components, the fifthpixel from the left contains five foreground components, the sixth pixelfrom the left contains five foreground components, the seventh pixelfrom the left contains five foreground components, the eighth pixel fromthe left contains five foreground components, the ninth pixel from theleft contains four foreground components, the tenth pixel from the leftcontains three foreground components, the eleventh pixel from the leftcontains two foreground components, and the twelfth pixel from the leftcontains one foreground component.

Instead of selecting a model from the prestored models, themodel-forming portion 902 may generate a model based on the motionvector and the unit of processing when the motion vector and the unit ofprocessing are supplied.

An equation generator 903 generates an equation based on the modelsupplied from the model-forming portion 902.

A description is now given, with reference to the models of foregroundcomponent images shown in FIGS. 88 through 90, of an example of theequation generated by the equation generator 903 when the number offoreground components is 8, the number of pixels corresponding to theunit of processing is 12, and the amount of movement v is 5.

When the foreground components contained in the foreground componentimage corresponding to the shutter time/v are F01/v through F08/v, therelationships between F01/v through F08/v and pixel values C01 throughC12 can be expressed by equations (78) through (89), as stated above.

By considering the pixel values C12 and C11, the pixel value C12contains only the foreground component F08/v, as expressed by equation(111), and the pixel value C11 consists of the product sum of theforeground component F08/v and the foreground component F07/v.Accordingly, the foreground component F07/v can be found by equation(112).F08/v=C12  (111)F07/v=C11−C12  (112)

Similarly, by considering the foreground components contained in thepixel values C10 through C01, the foreground components F06/v throughF01/v can be found by equations (113) through (118), respectively.F06/v=C10−C11  (113)F05/v=C09−C10  (114)F04/v=C08−C09  (115)F03/v=C07−C08+C12  (116)F02/v=C06−C07+C11−C12  (117)F01/v=C05−C06+C10−C11  (118)

The equation generator 903 generates the equations for calculating theforeground components by the difference between the pixel values, asindicated by the examples of equations (111) through (118). The equationgenerator 903 supplies the generated equations to the calculator 904.

The calculator 904 sets the pixel values of the foreground componentimage in the equations supplied from the equation generator 903 so as toobtain the foreground components based on the equations in which thepixel values are set. For example, when equations (111) through (118)are supplied from the equation generator 903, the calculator 904 setsthe pixel values C05 through C12 in equations (111) through (118).

The calculator 904 calculates the foreground components based on theequations in which the pixel values are set. For example, the calculator904 calculates the foreground components F01/v through F08/v, as shownin FIG. 89, based on the calculations of equations (111) through (118)in which the pixel values C05 through C12 are set. The calculator 904supplies the foreground components F01/v through F08/v to the adjustingportion 905.

The adjusting portion 905 multiplies the foreground components suppliedfrom the calculator 904 by the amount of movement v contained in themotion vector supplied from the unit-of-processing determining portion901 so as to obtain the foreground pixel values from which motion bluris eliminated. For example, when the foreground components F01/v throughF08/v are supplied from the calculator 904, the adjusting portion 905multiples each of the foreground components F01/v through F08/v by theamount of movement v, i.e., 5, so as to obtain the foreground pixelvalues F01 through F08 from which motion blur is eliminated, as shown inFIG. 90.

The adjusting portion 905 supplies the foreground component imageconsisting of the foreground pixel values without motion blur calculatedas described above to a motion-blur adder 906 and a selector 907.

The motion-blur adder 906 is able to adjust the amount of motion blur byusing the amount v′ by which motion blur is adjusted, which is differentfrom the amount of movement v, for example, the amount v′ by whichmotion blur is adjusted, which is one half the value of the amount ofmovement v, or the amount v′ by which motion blur is adjusted, which isirrelevant to the amount of movement v. For example, as shown in FIG.83, the motion-blur adder 906 divides the foreground pixel value Fiwithout motion blur by the amount v′ by which motion blur is adjusted soas to obtain the foreground component Fi/v′. The motion-blur adder 906then calculates the sum of the foreground components Fi/v′, therebygenerating the pixel value in which the amount of motion blur isadjusted. For example, when the amount v′ by which motion blur isadjusted is 3, the pixel value C02 is set to (F01)/v′, the pixel valueC3 is set to (F01+F02)/v′, the pixel value C04 is set to(F01+F02+F03)/v′, and the pixel value C05 is set to (F02+F03+F04)/v′.

The motion-blur adder 906 supplies the foreground component image inwhich the amount of motion blur is adjusted to the selector 907.

The selector 907 selects either the foreground component image withoutmotion blur supplied from the adjusting portion 905 or the foregroundcomponent image in which the amount of motion blur is adjusted suppliedfrom the motion-blur adder 906 based on a selection signal reflecting auser's selection, and outputs the selected foreground component image.

As discussed above, the motion-blur adjusting unit 106 is able to adjustthe amount of motion blur based on the selection signal and the amountv′ by which motion blur is adjusted.

The processing for adjusting the amount of motion blur of the foregroundexecuted by the motion-blur adjusting unit 106 configured as shown inFIG. 87 is described below with reference to the flowchart of FIG. 91.

In step S901, the unit-of-processing determining portion 901 of themotion-blur adjusting unit 106 generates the unit of processing based onthe motion vector and the area information, and supplies the generatedunit of processing to the model-forming portion 902 and the adjustingportion 905.

In step S902, the model-forming portion 902 of the motion-blur adjustingunit 106 selects or generates the model according to the amount ofmovement v and the unit of processing. In step S903, the equationgenerator 903 generates, based on the selected or generated model, theequations for calculating the foreground components by the differencebetween the pixel values of the foreground component image.

In step S904, the calculator 904 sets the pixel values of the foregroundcomponent image in the generated equations, and extracts the foregroundcomponents by using the difference between the pixel values based on theequations in which the pixel values are set. In step S905, thecalculator 904 determines whether all the foreground componentscorresponding to the unit of processing have been extracted. If it isdetermined that all the foreground components corresponding to the unitof processing have not been extracted, the process returns to step S904,and the processing for extracting the foreground components is repeated.

If it is determined in step S905 that all the foreground componentscorresponding to the unit of processing have been extracted, the processproceeds to step S906. In step S906, the adjusting portion 905 adjustseach of the foreground components F01/v through F08/v supplied from thecalculator 904 based on the amount of movement v so as to obtain theforeground pixel values F01/v through F08/v from which motion blur iseliminated.

In step S907, the motion-blur adder 906 calculates the foreground pixelvalues in which the amount of motion blur is adjusted, and the selector907 selects the image without motion blur or the image in which theamount of motion blur is adjusted, and outputs the selected image. Theprocessing is then completed.

As described above, the motion-blur adjusting unit 106 configured asshown in FIG. 87 is able to more speedily adjust motion blur of theforeground image containing motion blur according to simplercomputations.

A known technique for partially eliminating motion blur, such as aWiener filter, is effective when being used in the ideal state, but isnot sufficient for an actual image quantized and containing noise. Incontrast, it is proved that the motion-blur adjusting unit 106configured as shown in FIG. 87 is sufficiently effective for an actualimage quantized and containing noise. It is thus possible to eliminatemotion blur with high precision.

As described above, the separating portion 91, which is configured asshown in FIG. 9, can adjust the amount of motion blur contained in theinput image.

FIG. 92 is a block diagram illustrating another configuration of thefunction of the separating portion 91.

The elements similar to those shown in FIG. 9 are designated with likereference numerals, and an explanation thereof is thus omitted.

The area specifying unit 103 supplies area information to themixture-ratio calculator 104 and a synthesizer 1001.

The mixture-ratio calculator 104 supplies the mixture ratio α to theforeground/background separator 105 and the synthesizer 1001.

The foreground/background separator 105 supplies the foregroundcomponent image to the synthesizer 1001.

The synthesizer 1001 combines a certain background image with theforeground component image supplied from the foreground/backgroundseparator 105 based on the mixture ratio α supplied from themixture-ratio calculator 104 and the area information supplied from thearea specifying unit 103, and outputs the synthesized image in which thecertain background image and the foreground component image arecombined.

FIG. 93 illustrates the configuration of the synthesizer 1001. Abackground component generator 1021 generates a background componentimage based on the mixture ratio α and a certain background image, andsupplies the background component image to a mixed-area-imagesynthesizing portion 1022.

The mixed-area-image synthesizing portion 1022 combines the backgroundcomponent image supplied from the background component generator 1021with the foreground component image so as to generate a mixed-areasynthesized image, and supplies the generated mixture-area synthesizedimage to an image synthesizing portion 1023.

The image synthesizer 1023 combines the foreground component image, themixed-area synthesized image supplied from the mixed-area-imagesynthesizing portion 1022, and the certain background image based on thearea information so as to generate a synthesized image, and outputs it.

As discussed above, the synthesizer 1001 is able to combine theforeground component image with a certain background image.

The image obtained by combining a foreground component image with acertain background image based on the mixture ratio α, which is thefeature quantity, appears more natural compared to an image obtained bysimply combining pixels.

FIG. 94 is a block diagram illustrating another configuration of thefunction of the separating portion 91. The separating portion 91 shownin FIG. 9 sequentially performs the area-specifying operation and thecalculation for the mixture ratio α. In contrast, the separating portion91 shown in FIG. 94 simultaneously performs the area-specifyingoperation and the calculation for the mixture ratio α.

The functional elements similar to those indicated by the block of FIG.9 are indicated by like reference numerals, and an explanation thereofis thus omitted.

An input image is supplied to a mixture-ratio calculator 1101, aforeground/background separator 1102, the area specifying unit 103, andthe object extracting unit 101.

The mixture-ratio calculator 1101 calculates, based on the input image,the estimated mixture ratio when it is assumed that each pixel containedin the input image belongs to the covered background area, and theestimated mixture ratio when it is assumed that each pixel contained inthe input image belongs to the uncovered background area, and suppliesthe estimated mixture ratios calculated as described above to theforeground/background separator 1102.

FIG. 95 is a block diagram illustrating an example of the configurationof the mixture-ratio calculator 1101.

An estimated-mixture-ratio processor 401 shown in FIG. 95 is the same asthe estimated-mixture-ratio processor 401 shown in FIG. 54. Anestimated-mixture-ratio processor 402 shown in FIG. 95 is the same asthe estimated-mixture-ratio processor 402 shown in FIG. 54.

The estimated-mixture-ratio processor 401 calculates the estimatedmixture ratio for each pixel by the computation corresponding to a modelof the covered background area based on the input image, and outputs thecalculated estimated mixture ratio.

The estimated-mixture-ratio processor 402 calculates the estimatedmixture ratio for-each pixel by the computation corresponding to a modelof the uncovered background area based on the input image, and outputsthe calculated estimated mixture ratio.

The foreground/background separator 1102 generates the foregroundcomponent image from the input image based on the estimated mixtureratio calculated when it is assumed that the pixel belongs to thecovered background area supplied from the mixture-ratio calculator 1101,the estimated mixture ratio calculated when it is assumed that the pixelbelongs to the uncovered background area supplied from the mixture-ratiocalculator 1101, and the area information supplied from the areaspecifying unit 103, and supplies the generated foreground componentimage to the motion-blur adjusting unit 106 and the selector 107.

FIG. 96 is a block diagram illustrating an example of the configurationof the foreground/background separator 1102.

The elements similar to those of the foreground/background separator 105shown in FIG. 71 are indicated by like reference numerals, and anexplanation thereof is thus omitted.

A selector 1121 selects, based on the area information supplied from thearea specifying unit 103, either the estimated mixture ratio calculatedwhen it is assumed that the pixel belongs to the covered background areasupplied from the mixture-ratio calculator 1101 or the estimated mixtureratio calculated when it is assumed that the pixel belongs to theuncovered background area supplied from the mixture-ratio calculator1101, and supplies the selected estimated mixture ratio to theseparating portion 601 as the mixture ratio α.

The separating portion 601 extracts the foreground components and thebackground components from the pixel values of the pixels belonging tothe mixed area based on the mixture ratio α supplied from the selector1121 and the area information, and supplies the extracted foregroundcomponents to the synthesizer 603 and also supplies the foregroundcomponents to the synthesizer 605.

The separating portion 601 can be configured similarly to thecounterpart shown in FIG. 76.

The synthesizer 603 synthesizes the foreground component image andoutputs it. The synthesizer 605 synthesizes the background componentimage and outputs it.

The motion-blur adjusting unit 106 shown in FIG. 94 can be configuredsimilarly to the counterpart shown in FIG. 9. The motion-blur adjustingunit 106 adjusts the amount of motion blur contained in the foregroundcomponent image supplied from the foreground/background separator 1102based on the area information and the motion vector, and outputs theforeground component image in which the amount of motion blur isadjusted.

The selector 107 shown in FIG. 94 selects the foreground component imagesupplied from the foreground/background separator 1102 or the foregroundcomponent image in which the amount of motion blur is adjusted suppliedfrom the motion-blur adjusting unit 106 based on, for example, aselection signal reflecting a user's selection, and outputs the selectedforeground component image.

As discussed above, the separating portion 91 shown in FIG. 94 is ableto adjust the amount of motion blur contained in an image correspondingto a foreground object of the input image, and outputs the resultingforeground object image. As in the first embodiment, the separatingportion 91 having the configuration shown in FIG. 94 is able tocalculate the mixture ratio α, which is embedded information, andoutputs the calculated mixture ratio α.

FIG. 97 is a block diagram illustrating another configuration of thefunction of the separating portion 91 for combining a foregroundcomponent image with a certain background image. The separating portion91 shown in FIG. 92 serially performs the area-specifying operation andthe calculation for the mixture ratio α. In contrast, the separatingportion 91 shown in FIG. 97 performs the area-specifying operation andthe calculation for the mixture ratio α in a parallel manner.

The functional elements similar to those of the block diagram of FIG. 94are designated with like reference numerals, and explanation thereof isthus omitted.

The mixture-ratio calculator 1101 shown in FIG. 97 calculates, based onthe input image, the estimated mixture ratio when it is assumed thateach pixel contained in the input image belongs to the coveredbackground area, and the estimated mixture ratio when it is assumed thateach pixel contained in the input image belongs to the uncoveredbackground area, and supplies the estimated mixture ratios calculated asdescribed above to the foreground/background separator 1102 and asynthesizer 1201.

The foreground/background separator 1102 shown in FIG. 97 generates theforeground component image from the input image based on the estimatedmixture ratio calculated when it is assumed that the pixel belongs tothe covered background area supplied from the mixture-ratio calculator1101, the estimated mixture ratio calculated when it is assumed that thepixel belongs to the uncovered background area supplied from themixture-ratio calculator 1101, and the area information supplied fromthe area specifying unit 103, and supplies the generated foregroundcomponent image to the synthesizer 1201.

The synthesizer 1201 combines a certain background image with theforeground component image supplied from the foreground/backgroundseparator 1102 based on the estimated mixture ratio calculated when itis assumed that the pixel belongs to the covered background areasupplied from the mixture-ratio calculator 1101, the estimated mixtureratio calculated when it is assumed that the pixel belongs to theuncovered background area supplied from the mixture-ratio calculator1101, and the area information supplied from the area specifying unit103, and outputs the synthesized image in which the background image andthe foreground component image are combined.

FIG. 98 illustrates the configuration of the synthesizer 1201. Thefunctional elements similar to those indicated by the block of FIG. 93are indicated by like reference numerals, and an explanation thereof isthus omitted.

A selector 1221 selects, based on the area information supplied from thearea specifying unit 103, either the estimated mixture ratio calculatedwhen it is assumed that the pixel belongs to the covered background areasupplied from the mixture-ratio calculator 1101 or the estimated mixtureratio calculated when it is assumed that the pixel belongs to theuncovered background area supplied from the mixture-ratio calculator1101, and supplies the selected estimated mixture ratio to thebackground component generator 1021 as the mixture ratio α.

The background component generator 1021 shown in FIG. 98 generates abackground component image based on the mixture ratio α supplied fromthe selector 1221 and a certain background image, and supplies thebackground component image to the mixed-area-image synthesizing portion1022.

The mixed-area-image synthesizing portion 1022 shown in FIG. 98 combinesthe background component image supplied from the background componentgenerator 1021 with the foreground component image so as to generate amixed-area synthesized image, and supplies the generated mixed-areasynthesized image to the image synthesizing portion 1023.

The image synthesizing portion 1023 combines the foreground componentimage, the mixed-area synthesized image supplied from themixed-area-image synthesizing portion 1022, and the background imagebased on the area information so as to generate a synthesized image andoutputs it.

In this manner, the synthesizer 1201 is able to combine the foregroundcomponent image with a certain background image.

The embodiment has been discussed above by setting the mixture ratio αto the ratio of the background components contained in the pixel values.However, the mixture ratio α may be set to the ratio of the foregroundcomponents contained in the pixel values.

The embodiment has been discussed above by setting the moving directionof the foreground object to the direction from the left to the right.However, the moving direction is not restricted to the above-describeddirection.

In the above description, a real-space image having a three-dimensionalspace and time axis information is projected onto a time space having atwo-dimensional space and time axis information by using a video camera.However, the present invention is not restricted to this example, andcan be applied to the following case. When a greater amount of firstinformation in one-dimensional space is projected onto a smaller amountof second information in a two-dimensional space, distortion generatedby the projection can be corrected, significant information can beextracted, or a more natural image can be synthesized.

The sensor is not restricted to a CCD, and may be another type ofsensor, such as a solid-state image-capturing device, for example, a BBD(Bucket Brigade Device), a CID (Charge Injection Device), or a CPD(Charge Priming Device), or a CMOS (Complementary Metal OxideSemiconductor). Also, the sensor does not have to be a sensor in whichdetection devices are arranged in a matrix, and may be a sensor in whichdetection devices are arranged in one line.

Referring to the flowchart of FIG. 99, the synthesis service processingfor outputting a synthesized image generated by combining a foregroundcomponent image of an image captured in real time by the camera terminaldevice 2 with a specified background component image will now bedescribed. It is assumed that the camera terminal device 2 is rented outto a user. A case in which fees are separately charged for theseparation processing and the synthesis processing will now bedescribed.

In step S1001, it is determined whether or not a shutter button ispressed. The processing is repeated until it is determined that theshutter button is pressed. When the shutter button is pressed, in stepS1002, the signal controller 71 performs the processing to separate animage input from the image-capturing unit 74 into a background componentimage and a foreground component image. The image separation processingis a series of processes performed by the above-described separatingportion 91. Specifically, the processing is to separate the input imageinto the foreground component image and the background component imageand is implemented by the area specifying processing described withreference to the flowchart of FIG. 35, the mixture-ratio calculationprocessing described with reference to FIG. 63, theforeground/background separation processing described with reference tothe flowchart of FIG. 78, and the foreground-component-image-motion-bluradjustment processing described with reference to the flowchart of FIG.86. Since the processing is similar to the above, a description thereofis omitted.

In step S1003, the billing processor 75 performs the billing processingto charge fees to the billing server 5 via the network 1. At the sametime, in step S1021, the billing server 5 performs the billingprocessing to charge fees to the camera terminal device 2.

With reference to the flowchart of FIG. 100, the above-described billingprocessing will now be described. In the billing processing, the userwho has borrowed the camera terminal device 2 inputs, prior to the startof using the camera terminal device 2, for example, the user's accountID (credit card number may be input instead) and authenticationinformation.

In step S1101, as shown in FIG. 101, the billing processor 75 specifiesthe contents of the processing (service) and transmits ID informationfor identifying the user (user requesting image separation),authentication information (password and the like), fees, and ID storedtherein (ID for specifying the provider) to the billing server 5 via thenetwork 1. In this case, the image separation processing is specified asa service.

In step S1121, as shown in FIG. 101, the billing server 24 asks thefinancial server 6 under the management of a financial institutionhaving the customer's account about the authentication information, thecustomer's account ID, and the fees on the basis of the (user's) IDtransmitted from the camera terminal device 2.

In step S1141, as shown in FIG. 101, the financial server (for customer)6 performs the authentication processing based on the customer's accountID and the authentication information and informs the billing server 5of the authentication result and the service availability information.

In step S1122, as shown in FIG. 101, the billing server 5 transmits theauthentication information and the service availability information tothe camera terminal device 2. In the following description, the casewill be described under the conditions that there is no problem with theauthentication result and that the service is thus available. If thereis a problem with the authentication result and information indicatingthat the service is unavailable is received, the processing isterminated.

In step S1102, as shown in FIG. 101, the camera terminal device 2provides the service when the conditions that there is no problem withthe authentication result and that the service is thus available aresatisfied. In other words, in this case, the camera terminal device 2executes the image separation processing.

In step S1103, the camera terminal device 2 transmits a service usenotification to the billing server 5. In step S1123, the billing server5 informs the financial server (for customer) 6 of the customer'saccount ID, the fees, and the provider's account ID.

In step S1142, the financial server (for customer) 6 transfers the feesfrom an account with the customer's account ID to the provider'sfinancial server (for provider) 7.

The description returns to the flowchart of FIG. 99.

In step S1004, the signal controller 71 stores the separated images inthe image storage unit 72. In step S1005, the billing processor 75determines whether or not the shutter has been continuously pressed. Ifit is determined that the shutter has been continuously pressed, theprocessing returns to step S1002. That is, the billing processing iscontinuously executed while the shutter is continuously pressed.

If it is determined in step S1005 that the shutter is not pressed, instep S1006, the signal controller 71 determines whether or not the ID ofan image to be selected as a background component image is input. Theprocessing is repeated until the ID is input. The ID for specifying thebackground component image may be set prior to the start of using thecamera terminal device 2. When there is no preset ID, the ID specifiedby default may be input. Accordingly, the separation processing and thesynthesis processing are performed without an obstacle after the shutteris pressed.

In step S1007, the signal controller 71 combines the backgroundcomponent image having the specified ID with the foreground componentimage separated by the separation processing. For example, when an imageshown in FIG. 102A is captured by the image-capturing unit 74, thesignal controller 71 separates the image into a foreground componentimage and a background component image. Subsequently, as shown in FIG.102B, when the processing in step S1006 selects background B3 from amongimages stored in the image storage unit 72 (including backgrounds B1 toB3 and foregrounds F1 to F3), the signal controller 71 combinesbackground B3 and the foreground component image at the center of theimage shown in FIG. 102A to generate a synthesized image shown in FIG.102C.

In steps S1008 and S1022, the billing processor 71 of the cameraterminal device 2 and the billing server 5 perform the billingprocessing for charging fees for the synthesis processing. Since thebilling processing is similar to the processing described with referenceto the flowchart of FIG. 100, a description thereof is omitted.

In step S1009, the signal controller 71 of the camera terminal device 2displays the synthesized image on the display unit 73, assigns the ID tothe image, and stores the image in the image storage unit 72.

In the foregoing example, the separation processing is repeated for aperiod of time during which the shutter is pressed, and thecorresponding fees are continuously charged. Alternatively, fees may becharged every time the shutter is pressed.

The television set terminal device 3 for eliminating in real time motionblur of an image of a moving subject captured by the camera device 4 anddisplaying the motion-blur-eliminated image, as shown in FIG. 103, orfor eliminating motion blur in real time and combining themotion-blur-eliminated image with a background component image, as shownin FIG. 104, will now be described with reference to FIG. 105.

The television set terminal device 3 shown in FIG. 105 is, as shown inFIG. 104, to be rented out for use in wild animal observation at nightor the like. The billing processing charges, to the television setterminal device 3, fees based on renting time (fees in accordance withthe facility use time) and fees for the motion-blur eliminationprocessing and the synthesis processing. The fees for the motion-blurelimination processing and the synthesis processing are charged onlywhen there is a motion in the subject image (foreground componentimage).

A facility-use-time measuring unit 2001 of the television set terminaldevice 3 measures the time from the renting of the television setterminal device 3. The facility-use-time measuring unit 2001 stores themeasured time in a counter 2001 a and outputs the final measuredfacility use time to the billing processor 85. A still/motiondetermination unit 2002 scans the captured image input from the cameradevice 4 and determines whether or not there is a motion in the subjectimage (foreground component image). If there is a motion, thestill/motion determination unit 2002 outputs a signal indicating thepresence of the motion to a processing-time measuring unit 2003. Whenthe signal indicating the presence of the motion is input to theprocessing-time measuring unit 2003, the processing-time measuring unit2003 stores the time during which the signal is input in a counter 2003a and, finally in the billing processing, outputs the processing timestored in the counter 2003 a to the billing processor 85. At this time,the billing processor 85 calculates the fees in accordance with thefacility use time input from the facility-use-time measuring unit 2001and the processing time input from the processing-time measuring unit2003 and executes the billing processing to charge the fees to thebilling server 5.

Since the configuration of the signal processor 81 is similar to that ofthe signal processor 71 shown in FIG. 8, a description thereof isomitted.

Referring to the flowchart of FIG. 106, the real-time synthesis serviceprocessing performed by the television set terminal device 3 for use inwild animal observation at night will now be described.

In step S1201, the facility-use-time measuring unit 2001 of thetelevision set terminal device 3 starts measuring the facility use time.At this time, the camera device 4 starts outputting captured images oneafter another to the signal processor 71 and the still/motiondetermination unit 2002. In step S1202, the still/motion determinationunit 2002 determines whether or not there is a motion in the subject.The processing is repeated until it is determined that there is amotion. If it is determined that there is a motion, the processingproceeds to step S1203.

In step S1203, the still/motion determination unit 2002 outputs a signalindicating the detection of the motion. In response, the processing-timemeasuring unit 2003 starts measuring the processing time.

In step S1204, the separating portion 91 of the signal controller 81executes the processing to separate an input image. The processing issimilar to the processing in step S1002 of the flowchart of FIG. 99 andincludes the motion-blur adjustment processing (see the flowchart ofFIG. 86). With this processing, the image is separated, and motion bluris eliminated by the foreground-component-image-motion-blur adjustmentprocessing. In this case, after the image is separated, only theforeground component image is output to the synthesizer 92.

In step S1205, the synthesizer 92 reads a background component image tobe combined from the image storage unit 72. In step S1206, thesynthesizer 92 combines the read background component image and themotion-blur-eliminated foreground component image input from theseparating portion 91 to synthesize an image and outputs the synthesizedimage to the display unit 83. The display unit 83 displays thesynthesized image.

In step S1207, the still/motion determination unit 2002 determineswhether or not there is a motion, that is, whether or not there has beenintermittently a motion. If it is determined that there is a motion, theprocessing returns to step S1204, and the processing from this steponward is repeated.

If it is determined in step S1207 that there is no motion, in stepS1208, the processing-time measuring unit 2003 measures the time usedfor the actual separation processing (motion-blur eliminationprocessing) and the synthesis processing and stores the time in thecounter 2003 a.

In step S1209, the facility-use-time measuring unit 2001 determineswhether or not the use of the facility is ended. For example, when theuse of the facility is ended, in step S1210, the facility-use-timemeasuring unit 2001 measures the facility use time stored in the counter2001 a and outputs the measured time to the billing processor 75.

In steps S1211 and S1121, the billing processor 85 of the television setterminal device 3 and the billing server 5 calculate the fees based onthe facility use time and the processing time used for the motion-blurelimination processing and the synthesis processing and executes thecorresponding billing processing. Since the billing processing issimilar to the processing described with reference to the flowchart ofFIG. 100, a description thereof is omitted.

With the foregoing processing, a service for capturing amotion-blur-adjusted image in dim light, such as in wild animalobservation at night, is provided. Since the billing processing forcharging fees in accordance with renting time (facility use time) duringwhich the television set terminal device 3 is rented and processing time(time used for the motion blur processing and the synthesis processing)is implemented, fees for the separation processing and the synthesisprocessing are not charged at night during which animals remainstationary. The user only pays fees when a situation in which theseparation processing and the synthesis processing are necessary arises.

Alternatively, in the real-time synthesis service processing describedwith reference to the flowchart of FIG. 106, the billing processingcharges fees not based on renting time but only on processing time. Withreference to the flowchart of FIG. 107, the processing in which thetelevision set terminal device 3 is rented out to a user at a golfcourse or the like so as that the user can check the user's golf swingwill now be described.

The processing is similar to the flowchart of FIG. 106 from which stepsS1201 and S1210 are omitted. That is, in step S1301, the still/motiondetermination unit 2002 determines whether or not there is a motion inthe subject. The processing is repeated until it is determined thatthere is a motion. If it is determined that there is a motion, theprocessing proceeds to step S1302. In other words, the processing is notexecuted and the billing processing is not executed until the userswings a golf club.

In step S1302, the still/motion determination unit 2002 outputs a signalindicating the detection of the motion. In response, the processing-timemeasuring unit 2003 starts measuring the processing time.

In step S1303, the separating portion 91 of the signal controller 81executes the processing to separate an input image. The processing issimilar to the processing in step S1002 of the flowchart of FIG. 99 andincludes the motion-blur-amount adjustment processing. With thisprocessing, the image is separated, and motion blur is eliminated by theforeground-component-image-motion-blur adjustment processing.

In step S1304, the synthesizer 92 reads a background component image tobe combined from the image storage unit 82. In step S1305, thesynthesizer 92 combines the read background component image and themotion-blur-eliminated foreground component image input from theseparating portion 91 to synthesize an image and outputs the synthesizedimage to the display unit 83. The display unit 83 displays thesynthesized image. In this case, the result is satisfactory when motionblur due to the swinging of the golf club is eliminated from thedisplayed image. A captured image does not need to be combined with adifferent background component image. Accordingly, a backgroundcomponent image is not necessarily read from the image storage unit 82.

In step S1306, the still/motion determination unit 2002 determineswhether or not there is a motion, that is, whether or not there has beenintermittently a motion. If it is determined that there is a motion, theprocessing returns to step S1204, and the processing from this steponward is repeated.

If it is determined in step S1306 that there is no motion, in stepS1307, the processing-time measuring unit 2003 measures the time usedfor the actual separation processing (motion-blur eliminationprocessing) and the synthesis processing and stores the measured time inthe counter 2003 a.

In step S1308, the facility-use-time measuring unit 2001 determineswhether or not the use of the facility is ended. For example, when theuse of the facility is ended (when the camera terminal device 2 is to bereturned), in steps S1309 and S1321, the billing processor 71 of thecamera terminal device 2 and the billing server 5 calculate the feesbased on the facility use time and the processing time used for themotion-blur elimination processing and the synthesis processing andexecutes the corresponding billing processing. Since the billingprocessing is similar to the processing described with reference to theflowchart of FIG. 100, a description thereof is omitted.

In the foregoing description, the operation of the television setterminal device 3 has been described. Alternatively, for example,similar processing may be performed by the camera terminal device 2.

Accordingly, the separating portion 91 of the present inventionseparates in real time a captured image into a foreground componentimage (foreground component image) and a foreground component image(foreground component image) and performs in real time the motion-bluradjustment processing of the foreground component image.

A recording medium in which a program for performing the signalprocessing of the present invention is recorded may be formed of apackage medium in which the program is recorded, which is distributedfor providing the program to a user separately from the computer, asshown in FIGS. 4 and 5, such as the magnetic disks 41 and 61 (includinga flexible disk), the optical discs 42 and 62 (including a CD-ROM(Compact Disc-Read Only Memory) and a DVD (Digital Versatile Disc)), themagneto-optical disks 43 and 63 (including an MD (Mini-Disc) (registeredtrade name)), or the semiconductor memories 44 and 64. The recordingmedium may also be formed of the ROMs 22 and 52 or hard disks containedin the storage units 28 and 58 in which the program is recorded, suchrecording medium being provided to the user while being prestored in thecomputer.

The steps forming the program recorded in a recording medium may beexecuted chronologically according to the orders described in thespecification. However, they do not have to be executed in a time-seriesmanner, and they may be executed concurrently or individually.

INDUSTRIAL APPLICABILITY

According to the present invention, a captured image is separated inreal time into a foreground component image (foreground component image)and a foreground component image (foreground component image), and themotion-blur adjustment processing of the foreground component image isperformed in real time.

1. An image processing apparatus comprising: an input for inputtingimage data which is formed of a predetermined number of pixel dataobtained by a predetermined number of image-capturing devices includingpixels, the image-capturing devices each having a time integratingfunction; a mixture-ratio estimator for estimating a mixture ratio for amixed area in the input image data, the mixed area including a mixtureof foreground object components forming a foreground object of the imagedata and background object components forming a background object of theimage data; a separator for separating in real time, on the basis of theestimated mixture ratio, the input image into a foreground componentimage formed of the foreground object components forming the foregroundobject of the image data and a background component image formed of thebackground object components forming the background object of the imagedata; and a store for storing in real time the foreground componentimage and the background component image, which are separated by theseparator.
 2. The image processing apparatus according to claim 1,further comprising an image-capturing unit for capturing an image whichis formed of the image data formed of pixel values determined inaccordance with the intensity of light forming the image which isintegrated with respect to time in each pixel by the predeterminednumber of image-capturing devices for converting the light forming theimage into electrical charge and integrating with respect to time theelectrical charge generated by the photoelectric conversion.
 3. Theimage processing apparatus according to claim 2, further comprising: animage-capturing commander for giving a command to the image-capturingunit to capture the image; and a billing unit for executing billingprocessing in response to the command from the image-capturingcommander.
 4. The image processing apparatus according to claim 1,further comprising: a display for displaying the foreground componentimage and the background component image which are separated in realtime by the separator and the foreground component image and thebackground component image which are already stored in the store; animage specifier for specifying a desired foreground component image andbackground component image from among the foreground component image andthe background component image which are separated in real time by theseparator and which are displayed by the display and the foregroundcomponent image and the background component image which are alreadystored in the store and which are displayed by the display; and acombiner for combining the desired foreground component image andbackground component image which are specified by the specifier.
 5. Theimage processing apparatus according to claim 4, further comprising: acommand unit for giving a command to the combiner to combine images; anda billing unit for executing billing processing in response to thecommand from the command unit.
 6. The image processing apparatusaccording to claim 1, further comprising: a storage command unit forgiving a command to the store, the command instructing whether or not tostore in real time the foreground component image and the backgroundcomponent image which are separated by the separator; and a storagebilling unit for executing billing processing in response to the commandfrom the storage command unit.
 7. The image processing apparatusaccording to claim 1, further comprising: a motion-blur adjusting unitfor adjusting motion blur of the foreground component image which isseparated in real time by the separator or the foreground componentimage which is already stored in the store.
 8. The image processingapparatus according to claim 7, further comprising: amotion-blur-adjusted display for displaying the motion-blur-adjustedforeground component image generated by the motion-blur adjusting unit.9. The image processing apparatus according to claim 8, furthercomprising: a combiner for combining the motion-blur-adjusted foregroundcomponent image generated by the motion-blur adjusting unit and thebackground component image, wherein the motion-blur-adjusted displaydisplays an image generated by combining, by the combiner, themotion-blur-adjusted foreground component image generated by themotion-blur adjusting unit and the background component image.
 10. Theimage processing apparatus according to claim 7, further comprising: ameasuring unit for measuring time required by the motion-blur adjustingunit to adjust the motion blur of the foreground component image; and amotion-blur-adjustment billing unit for executing billing processing inaccordance with the time measured by the measuring unit.
 11. The imageprocessing apparatus according to claim 8, further comprising: anoperation-time measuring unit for measuring operation time thereof; andan operation billing unit for executing billing processing in accordancewith the time measured by the operation-time measuring unit.
 12. Animage processing method comprising: an input step of inputting imagedata which is formed of a predetermined number of pixel data obtained bya predetermined number of image-capturing devices including pixels, theimage-capturing devices each having a time integrating function; amixture-ratio estimating step of estimating a mixture ratio for a mixedarea in the image data input in the input step, the mixed area includinga mixture of foreground object components forming a foreground object ofthe image data and background object components forming a backgroundobject of the image data; a separation step of separating in real time,on the basis of the mixture ratio estimated in the mixture-ratioestimating step, the image data input in the input step into aforeground component image formed of the foreground object componentsforming the foreground object of the image data and a backgroundcomponent image formed of the background object components forming thebackground object of the image data; and a storage step of storing inreal time the foreground component image and the background componentimage, which are separated in the separation step.
 13. An imageprocessing method according to claim 12, further comprising: animage-capturing step of capturing an image which is formed of the imagedata formed of pixel values determined in accordance with the intensityof light forming the image which is integrated with respect to time ineach pixel by the predetermined number of image-capturing devices forconverting the light forming the image into electrical charge andintegrating with respect to time the electrical charge generated by thephotoelectric conversion.
 14. An image processing method according toclaim 13, further comprising: an image-capturing command step of givinga command to the image-capturing step to capture the image; and animage-capturing billing step of executing billing processing in responseto the command in the image-capturing command step.
 15. An imageprocessing method according to claim 12, further comprising: an imagedisplay step of displaying the foreground component image and thebackground component image which are separated in real time in theseparation step and the foreground component image and the backgroundcomponent image which are already stored in the storage step; an imagespecifying step of specifying a desired foreground component image andbackground component image from among the foreground component image andthe background component image which are separated in real time in theseparation step and which are displayed in the image display step andthe foreground component image and the background component image whichare already stored in the storage step and which are displayed in theimage display step; and a combining step of combining the desiredforeground component image and background component image which arespecified in the specifying step.
 16. An image processing methodaccording to claim 15, further comprising: a combining command step ofgiving a command to the combining step to combine images; and acombining billing step of executing billing processing in response tothe command in the combining command step.
 17. An image processingmethod according to claim 12, further comprising: a storage command stepof giving a command to the storage step, the command instructing whetheror not to store in real time the foreground component image and thebackground component image which are separated in the separation step;and a storage billing step of executing billing processing in responseto the command in the storage command step.
 18. An image processingmethod according to claim 12, further comprising: a motion-bluradjusting step of adjusting motion blur of the foreground componentimage which is separated in real time in the separation step or theforeground component image which is already stored in the storage step.19. An image processing method according to claim 18, furthercomprising: a motion-blur-adjusted-image display step of displaying themotion-blur-adjusted foreground component image generated in themotion-blur adjusting step.
 20. An image processing method according toclaim 19, further comprising: a combining step of combining themotion-blur-adjusted foreground component image generated in themotion-blur adjusting step and the background component image, whereinthe motion-blur-adjusted-image display step displays an image generatedby combining, in the combining step, the motion-blur-adjusted foregroundcomponent image generated in the motion-blur adjusting step and thebackground component image.
 21. An image processing method according toclaim 18, further comprising: a processing-time measuring step ofmeasuring time required by the motion-blur adjusting step to adjust themotion blur of the foreground component image; and amotion-blur-adjustment billing step of executing billing processing inaccordance with the time measured in the processing-time measuring step.22. An image processing method according to claim 19, furthercomprising: an operation-time measuring step of measuring operation timethereof; and an operation billing step of executing billing processingin accordance with the time measured in the operation-time measunngstep.
 23. A computer-readable medium storing a computer program tocontrol a processor to carry out a method comprising: an input controlstep of controlling the inputting of image data which is formed of apredetermined number of pixel data obtained by a predetermined number ofimage-capturing devices including pixels, the image-capturing deviceseach having a time integrating function; a mixture-ratio estimatingcontrol step of controlling the estimation of a mixture ratio for amixed area in the image data input in the input control step, the mixedarea including a mixture of foreground object components forming aforeground object of the image data and background object componentsforming a background object of the image data; a separation control stepof controlling the separation in real time, on the basis of the mixtureratio estimated in the mixture-ratio estimating control step, of theimage data input in the input control step into a foreground componentimage formed of the foreground object components forming the foregroundobject of the image data and a background component image formed of thebackground object components forming the background object of the imagedata; and a storage control step of controlling the storing, in realtime, of the foreground component image and the background componentimage, which are separated in the separation control step.
 24. Thecomputer-readable medium according to claim 23 having recorded thereon acomputer-readable program, the program further comprising: animage-capturing control step of controlling the capturing of an imagewhich is formed of the image data formed of pixel values determined inaccordance with the intensity of light forming the image which isintegrated with respect to time in each pixel by the predeterminednumber of image-capturing devices for converting the light forming theimage into electrical charge and integrating with respect to time theelectrical charge generated by the photoelectric conversion.
 25. Thecomputer-readable medium according to claim 24 having recorded thereon acomputer-readable program, the program further comprising: animage-capturing command control step of controlling the giving of acommand to the image-capturing control step to capture the image; and animage-capturing billing control step of controlling the execution ofbilling processing in response to the command in the image-capturingcommand control step.
 26. The computer-readable medium according toclaim 23 having recorded thereon a computer-readable program, theprogram further comprising: an image display control step of controllingthe displaying of the foreground component image and the backgroundcomponent image which are separated in real time in the separationcontrol step and the foreground component image and the backgroundcomponent image which are already stored in the storage control step; animage specifying control step of controlling the specifying of a desiredforeground component image and background component image from among theforeground component image and the background component image which areseparated in real time in the separation control step and which aredisplayed in the image display control step and the foreground componentimage and the background component image which are already stored in thestorage control step and which are displayed in the image displaycontrol step; and a combining control step of controlling the combiningof the desired foreground component image and background component imagewhich are specified in the specifying control step.
 27. Thecomputer-readable medium according to claim 26 having recorded thereon acomputer-readable program, the program further comprising: a combiningcommand control step of controlling the giving of a command to thecombining control step to combine images; and a combining billingcontrol step of controlling the execution of billing processing inresponse to the command in the combining command control step.
 28. Thecomputer-readable medium according to claim 23 having recorded thereon acomputer-readable program, the program further comprising: a storagecommand control step of controlling the giving of a command to thestorage control step, the command instructing whether or not to store inreal time the foreground component image and the background componentimage which are separated in the separation control step; and a storagebilling control step of controlling the execution of billing processingin response to the command in the storage command control step.
 29. Thecomputer-readable medium according to claim 23 having recorded thereon acomputer-readable program, the program further comprising: a motion-bluradjusting control step of controlling the adjustment of motion blur ofthe foreground component image which is separated in real time in theseparation control step or the foreground component image which isalready stored in the storage control step.
 30. The computer-readablemedium according to claim 29 having recorded thereon a computer-readableprogram, the program further comprising: a motion-blur-adjusted-imagedisplay control step of controlling the displaying of themotion-blur-adjusted foreground component image generated in themotion-blur adjusting control step.
 31. The computer-readable mediumaccording to claim 30 having recorded thereon a computer-readableprogram, the program further comprising: a combining control step ofcontrolling the combining of the motion-blur-adjusted foregroundcomponent image generated in the motion-blur adjusting control step andthe background component image, wherein the motion-blur-adjusted-imagedisplay control step controls the display of an image generated bycombining, in the combining control step, the motion-blur-adjustedforeground component image generated in the motion-blur adjustingcontrol step and the background component image.
 32. Thecomputer-readable medium according to claim 29 having recorded thereon acomputer-readable program, the program further comprising: aprocessing-time measuring control step of controlling the measurement oftime required by the motion-blur adjusting control step to adjust themotion blur of the foreground component image; and amotion-blur-adjustment billing control step of controlling the executionof billing processing in accordance with the time measured in theprocessing-time measuring control step.
 33. The computer-readable mediumaccording to claim 30 having recorded thereon a computer-readableprogram, the program further comprising: an operation-time measuringcontrol step of controlling the measurement of operation time thereof;and an operation billing control step of controlling the execution ofbilling processing in accordance with the time measured in theoperation-time measuring control step.
 34. A program embodied in acomputer-readable medium for instructing a computer to perform a processcomprising: an input control step of controlling the inputting of imagedata which is formed of a predetermined number of pixel data obtained bya predetermined number of image-capturing devices including pixels, theimage-capturing devices each having a time integrating function; amixture-ratio estimating control step of controlling the estimation of amixture ratio for a mixed area in the image data input in the inputcontrol step, the mixed area including a mixture of foreground objectcomponents forming a foreground object of the image data and backgroundobject components forming a background object of the image data; aseparation control step of controlling the separation in real time, onthe basis of the mixture ratio estimated in the mixture-ratio estimatingcontrol step, of the image data input in the input control step into aforeground component image formed of the foreground object componentsforming the foreground object of the image data and a backgroundcomponent image formed of the background object components forming thebackground object of the image data; and a storage control step ofcontrolling the storing, in real time, of the foreground component imageand the background component image, which are separated in theseparation control step.
 35. The program according to claim 34 forinstructing a computer to perform a process further comprising: animage-capturing control step of controlling the capturing of an imagewhich is formed of the image data formed of pixel values determined inaccordance with the intensity of light forming the image which isintegrated with respect to time in each pixel by the predeterminednumber of image-capturing devices for converting the light forming theimage into electrical charge and integrating with respect to time theelectrical charge generated by the photoelectric conversion.
 36. Theprogram according to claim 35 for instructing a computer to perform aprocess further comprising: an image-capturing command control step ofcontrolling the giving of a command to the image-capturing control stepto capture the image; and an image-capturing billing control step ofcontrolling the execution of billing processing in response to thecommand in the image-capturing command control step.
 37. The programaccording to claim 34 for instructing a computer to perform a processfurther comprising: an image display control step of controlling thedisplaying of the foreground component image and the backgroundcomponent image which are separated in real time in the separationcontrol step and the foreground component image and the backgroundcomponent image which are already stored in the storage control step; animage specifying control step of controlling the specifying of a desiredforeground component image and background component image from among theforeground component image and the background component image which areseparated in real time in the separation control step and which aredisplayed in the image display control step and the foreground componentimage and the background component image which are already stored in thestorage control step and which are displayed in the image displaycontrol step; and a combining control step of controlling the combiningof the desired foreground component image and background component imagewhich are specified in the specifying control step.
 38. The programaccording to claim 37 for instructing a computer to perform a processfurther comprising: a combining command control step of controlling thegiving of a command to the combining control step to combine images; anda combining billing control step of controlling the execution of billingprocessing in response to the command in the combining command controlstep.
 39. The program according to claim 34 for instructing a computerto perform a process further comprising: a storage command control stepof controlling the giving of a command to the storage control step, thecommand instructing whether or not to store in real time the foregroundcomponent image and the background component image which are separatedin the separation control step; and a storage billing control step ofcontrolling the execution of billing processing in response to thecommand in the storage command control step.
 40. The program accordingto claim 34 for instructing a computer to perform a process furthercomprising: a motion-blur adjusting control step of controlling theadjustment of motion blur of the foreground component image which isseparated in real time in the separation control step or the foregroundcomponent image which is already stored in the storage control step. 41.The program according to claim 40 for instructing a computer to performa process further comprising: a motion-blur-adjusted-image displaycontrol step of controlling the displaying of the motion-blur-adjustedforeground component image generated in the motion-blur adjustingcontrol step.
 42. The program according to claim 41 for instructing acomputer to perform a process further comprising: a combining controlstep of controlling the combining of the motion-blur-adjusted foregroundcomponent image generated in the motion-blur adjusting control step andthe background component image, wherein the motion-blur-adjusted-imagedisplay control step controls the display of an image generated bycombining, in the combining control step, the motion-blur-adjustedforeground component image generated in the motion-blur adjustingcontrol step and the background component image.
 43. The programaccording to claim 40 for instructing a computer to perform a processfurther comprising: a processing-time measuring control step ofcontrolling the measurement of time required by the motion-bluradjusting control step to adjust the motion blur of the foregroundcomponent image; and a motion-blur-adjustment billing control step ofcontrolling the execution of billing processing in accordance with thetime measured in the processing-time measuring control step.
 44. Theprogram according to claim 41 for instructing a computer to perform aprocess further comprising: an operation-time measuring control step ofcontrolling the measurement of operation time thereof; and an operationbilling control step of controlling the execution of billing processingin accordance with the time measured in the operation-time measuringcontrol step.